Images from the Champions League matches played across Europe on Tuesday
Liverpool 's title defence begins with Napoli defeat
Juergen Klopp was frustrated by Liverpool’s poor finishing after his side began their Champions League title defence with a 2-0 defeat away to Napoli, who scored two late goals at the Stadio San Paolo on Tuesday.
Dries Mertens scored from the penalty spot with eight minutes remaining after Andy Robertson tripped Jose Callejon inside the box and Napoli substitute Fernando Llorente added a second in stoppage time to put the result beyond doubt.
Klopp’s side became the first competition winners to lose the opening game of their Champions League defence since AC Milan were defeated by Ajax Amsterdam in 1994 and the German was concerned by his players' wastefulness.
"It should hurt because there were opportunities for us,” he told BT Sport.
“It was an open game with a lot of counter attacks, but we didn't finish them off and that is a problem. In the second half it was a wild game, they were running and we were running."
Klopp was also unhappy about the penalty awarded to the home side after Robertson was adjudged to have fouled Callejon.
"I don't think it's a penalty,” he said.
“What can I say, for me, it is clear and obvious no penalty. He jumps before any contact, we can't change that.”
Napoli's Hirving Lozano headed in from close range early on but the goal was correctly ruled out for offside, before Sadio Mane forced home keeper Alex Meret into a save and Roberto Firmino flashed a header wide before the break.
Liverpool keeper Adrian denied Mertens with a superb reaction stop early in the second half before Meret dived to direct Mohamed Salah's effort wide.
But the late double from Mertens and Llorente secured the three points for Carlo Ancelotti’s side, who also beat Liverpool at home at the same stage last season.
“We worked hard to defend and attack as a unit, because at times football means adapting to situations and I think we did it well,” Ancelotti told Sky Sport Italia.
“We felt confident on the second goal, it was near the end and we were a goal up. You can press high at times, not at others, it’s about maintaining your identity and also being able to do everything. I liked our quality, but also how we played ugly when we needed to.”
In the other Group E game, Salzburg made an impressive start with a 6-2 victory at home to Genk.
Erling Haaland scored a first-half hat-trick for the Austrian champions, becoming the third youngest player to net a Champions League treble at the age of 19 years and 58 days, behind Raul (18y 113d) and Wayne Rooney (18y 340d).
Unlucky Dortmund draw 0-0 with Barca on Messi return
Borussia Dortmund hit the woodwork and had a penalty saved before drawing 0-0 with Barcelona in their Champions League Group F opener on Tuesday, with Lionel Messi making his first appearance of the season for the Spaniards.
Barca's in-form 16-year-old Ansu Fati became the club's youngest player to feature in a UEFA competition when he started but failed to make any real impact before being replaced by fit-again Messi just before the hour mark.
Even with the Argentine on the field it was the Germans who were more dangerous after captain Marco Reus' 57th minute penalty was saved by Marc Andre ter Stegen.
Reus was denied twice more by Ter Stegen and Julian Brandt rattled the crossbar with a thundering shot in the 77th.
"It feels terrible," Reus told reporters.
"My penalty was badly taken. We could have won it as our performance was good. It would have been the ideal start. But we can build on this."
Finding space in or around the box was virtually impossible for either side in the first half and the expected fireworks between two sides known for their attacking game never materialised.
Dortmund's Jadon Sancho was subdued while Fati showed none of the scoring form that has turned him into the latest football sensation in Spain.
It took Dortmund 25 minutes to carve out their first chance with a fine Thorgan Hazard through ball that sent Reus into the area but his Germany team mate Ter Stegen got the better of him.
Luis Suarez wriggled into the box to create a rare chance and tried to surprise Roman Buerki with a clever shot from a tight angle but the Dortmund keeper did well to guard the near post and palm the Uruguayan's effort wide.
Dortmund, who kept a clean sheet at home through the group stage last season, were then awarded a spot kick when Sancho was brought down but Ter Stegen picked the right corner to stop Reus' penalty. He was on hand again later to block a Reus shot.
Messi's introduction on the hour in the forward's first game since his pre-season injury, gave the Spaniards more pace and he made some darting runs but did not create enough for a goal.
"We suffered a lot," Barca coach Ernesto Valverde told reporters. "It was something we already knew would happen. We lacked depth in the last metres and we did not have as many chances as they had. Fortunately Marc was very good."
In the group's earlier game Inter Milan were surprisingly held to a 1-1 home draw by Slavia Prague.
Barkley misses penalty in Chelsea home defeat to Valencia
Valencia spoiled Frank Lampard's managerial debut in the Champions League by earning a morale-boosting 1-0 win at Chelsea on Tuesday after Ross Barkley spurned a chance to equalise by missing from the penalty spot.
Spain forward Rodrigo Moreno gave the visitors the lead against the run of play in the 74th minute of the Group H game, getting the slightest of touches on a free kick from Dani Parejo to send the ball into the roof of the net.
Chelsea continued to threaten and were awarded a penalty after a VAR review spotted a handball by Valencia defender Daniel Wass.
But Barkley sent the resulting spot kick on to the crossbar and over and Europa League holders Chelsea fell to their first home defeat in European competition since losing to Paris St Germain in March 2016.
"We shouldn't lose the game. Clearly," Lampard told reporters.
"We had a fair few chances and then the penalty, which we miss. We have to keep our heads up. There is a long way to go and this is a lesson that teams at this level can hurt you."
Lampard became the first Chelsea manager to lose his debut Champions League match in charge –- 10 of the previous 11 had won, while Gianluca Vialli drew with AC Milan in 1999.
Valencia travelled to London reeling from a stinging 5-2 league loss at Barcelona in coach Albert Celades's first game in charge after the much-loved Marcelino was sacked, despite overseeing two top-four finishes and winning the Copa del Rey.
His dismissal bewildered the players, who began a media blackout after the decision, while influential defender Ezequiel Garay fiercely criticised the move in an angry post on social media.
But the Spanish side leave the English capital emboldened and with three points after producing a solid, professional display and celebrating their triumph with their small band of travelling supporters tucked in a corner of StamfordBridge.
"It's difficult to forget about everything that has happened but I thank the players for welcoming me and their professionalism," coach Celades said.
"We are going to get back to normality little by little and I was hugely impressed by the effort we put in today. It was not the ideal situation but we have tried to close ranks and look forward."
Lampard's side went into the game in confident mood after beating Wolverhampton Wanderers 5-2 in the Premier League on Saturday and their supporters belted out the manager's name in his first Champions League game as a coach, after he won the competition in 2012 as a Chelsea player.
Visiting goalkeeper Jasper Cillessen was forced to make a pair of impressive saves to prevent the Londoners from taking the lead, turning away a powerful strike from Willian right before halftime.
The Dutchman then twice thwarted Marcos Alonso, parrying a low free kick early in the second half and tipping another set-piece effort from the Spaniard over the bar in stoppage time.
Chelsea were also dealt a setback with an ankle injury to in-form midfielder Mason Mount, who had to be taken off in the first half after a rash challenge from Valencia's Francis Coquelin.
Big win for Ajax Amsterdam
Ajax Amsterdam gave a powerful reminder of their Champions League potential with a resounding 3-0 win over Lille in Amsterdam on Tuesday at the start of the group phase.
Last season’s surprise package look hellbent on a repeat of their heroics, which got them all the way from the preliminary rounds to the semi-finals, and goals from Quincy Promes, Edson Alvarez and Nicolas Tagliafico ensured an emphatic start to Group H.
Having come through the preliminary rounds again, Ajax went ahead when Promes, one of their new signings, powered home a header after 18 minutes, getting in between two Lille defenders at the back post to finish off Tagliafico’s cross.
Alvarez, also bought since last season’s run to the final four of the Champions League, added the second goal in the 50th minute as David Neres slipped him in with a short pass and the Mexican international hooked a stinging shot in from a tight angle.
Fullback Tagliafico, one of the smallest on the pitch at 1.73 metres, then rose majestically to head home Hakim Ziyech’s 62nd-minute corner and extend the Dutch club’s lead.
Lille, back in the Champions League for the first time since the 2012-13 season, had chances but saw Jonathan Ikone, Victor Osimhen and Mehmet Zeki Celik all hit good efforts straight at Ajax goalkeeper Andre Onana.
In the last minute, substitute Yusuf Yazici crashed a shot against the upright but then hit the rebound over the top in the closest that last season’s Ligue 1 runners-up came to a consolation goal.
Ajax are next away at Valencia on October 2 while Lille host Chelsea the same night.
Barella rescues Inter with stoppage-time equaliser against Slavia
Substitute Nicolo Barella scored a stoppage-time equaliser on his Champions League debut to rescue a dramatic 1-1 draw for Inter Milan at home to Slavia Prague in their opening Champions League group game on Tuesday.
The Czech champions, beaten on all six previous visits to Italy, took a shock lead through Peter Olayinka in the 63rd minute to stun the San Siro in the Group F match.
Inter, eliminated in the group stage last season, were struggling to find a reply until Barella fired in the rebound in the second minute of stoppage time.
Despite Inter's relief, they may still come to regret the loss of two home points in a group which also includes Borussia Dortmund and Barcelona.
"That wasn't our football," said Inter coach Antonio Conte who saw his 100 percent record ended in his fourth game at the club.
"We need more personality and we need to improve."
"We didn't do any of what we practised and I am absolutely not satisfied. We have so much work to do."
Stefan de Vrij and Danilo D'Ambrosio both missed good chances for Inter in the opening half hour before Slavia Prague, Europa League quarter-finalists last season, began to impose themselves.
They took a deserved lead as Olayinka cut the ball back to Jaroslav Zeleny whose shot was saved by Samir Handanovic and fell to the Nigerian, who turned in the rebound.
Nicolae Stanciu nearly added a second from a free kick but it was Inter who levelled.
Stefano Sensi curled a free kick against the crossbar and the rebound fell kindly to Barella, who met it first time and scored with a shot which bounced into the net.
"If we look at the whole match, then the draw is probably fair, because Inter had some chances too," said Slavia defender Vladimir Coufal.
"But after we survived this, it is a big pity to concede such an equaliser during added time."
Lyon held by Zenit in disappointing start to Champions League
Olympique Lyonnais started their Champions League group stage campaign in disappointing fashion as they were held to a 1-1 home draw by Zenit St Petersburg on Tuesday.
Memphis Depay's penalty cancelled out Sardar Azmoun's first-half opener as the French side, who have drawn six straight home Champions League games, dominated after the break without inflicting any serious damage on their opponents.
Zenit, who have now failed to win any of their last 10 European away games, dominated Lyon's midfield in the first half before running out of gas.
Benfica play Leipzig in the other Group G game later on Tuesday.
Zenit caught the Lyon defence snoozing in the 41st minute when Azmoun found the back of the net with a low shot after a quick one-two with Artem Dzyuba.
Although they struggled in the midfield, Lyon levelled five minutes into the second half when Depay converted a penalty after being brought down by Magomed Ozdoev.
The hosts went close to taking the lead on the hour but Jeff Reine-Adelaide shot just wide after a clever cut-back from Lucas Tousart.
Lyon pushed harder in the closing stages but lacked a killer instinct to wrap up all three points. The French side next travel to Leipzig on Oct. 2 when Zenit will host Benfica.
Werner's second-half double for Leipzig sinks Benfica
RB Leipzig forward Timo Werner scored two second-half goals to secure an impressive 2-1 win at Benfica in their opening Champions League Group D match on Tuesday.
The 23-year-old finished off a neat Leipzig move to break the deadlock in the 69th minute after Nordi Mukiele threaded the ball into the area where Yussuf Poulsen laid it off for Werner to drive a low shot into the far corner.
Nine minutes later, the ball was chipped over the Benfica defence to release Marcel Sabitzer and he rolled into the path of Werner who scored again for the Bundesliga side.
The goal was initially disallowed for offside but awarded after quick a VAR review.
Benfica had threatened either side of Werner's opener. Pizzi nearly gave the Eagles the lead with a shot which flashed across the face of goal and Alex Grimaldo saw a dipping free kick brilliantly turned away by Peter Gulacsi immediately afterwards.
The Portuguese side finally scored in the 84th minute when a quick break ended with substitute Haris Seferovic firing past Gulacsi but they could not force an equaliser.
Leipzig top the group ahead of Olympique Lyonnais and Zenit St Petersburg who earlier drew 1-1 in the group's other match.