Out-of-sorts Chelsea have a golden opportunity to restore battered self-confidence when they face Maccabi Tel Aviv in their opening Champions League Group G match.
Liverpool blew a chance take a vice-like grip on the title race and Chelsea suffered their worst league defeat in 23 years.
A round-up of Saturday's matches in the English Premier League.
Jose Mourinho is starting to feel drained at having to watch his Chelsea team hang on for scrambling victories despite dominating opponents, the manager said after Thursday's 1-0 Premier League win over Swansea City.
With dreams of European glory in tatters, Manchester United, Chelsea and Tottenham Hotspur turn their attention to the FA Cup quarter-finals this weekend clinging to their last chance of silverware this season.
It is time to deliver for Paris St Germain and Manchester City as the two mega-rich teams prepare to lock horns in the first leg of their Champions League quarter-final.
Manchester United's Jose Mourinho, humbled for the second time this season in front of the Chelsea fans who once idolised him, did not go quietly on Monday as he declared that he remains the London club's number one manager.
Liverpool opened up a seven-point gap at the top of the English Premier League with a 1-0 win at Brighton & Hove Albion on Saturday, while Arsenal's poor away form continued with a 1-0 defeat at West Ham United.
Chelsea's Jose Mourinho, who hoped to celebrate his new contract with victory at an expectant Stamford Bridge, ended up grateful his team did not become the first Premier League champions to start their title defence with a defeat.
Chelsea banking on other big strikers with Costa still doubtful
Arsenal manager Arsene Wenger has apologised for shoving his Chelsea counterpart Jose Mourinho on the touchline during a Premier League match at Stamford Bridge.
Manchester United won away for the first time this season when they beat Arsenal 2-1 at the Emirates Stadium on Saturday to climb to fourth in the Premier League table.
Manchester City stumbled to the most unexpected defeat of the Premier League season on Saturday before neighbours Manchester United began their brave new world under Ole Gunnar Solskjaer with a glorious reminder of long-forgotten attacking swagger.
Liverpool will attempt to sweep away the January blues on the last day of a wretched month when they host commanding Premier League leaders Chelsea at Anfield on Tuesday.
Champions Chelsea begin title defence at home to Swansea City, while runners-up Manchester City kick-off at West Bromwich Albion
Arsenal fought back from a goal down against old foes Chelsea to reach the League Cup final as Granit Xhaka poked home to complete a 2-1 second-leg win on Wednesday that set up a Wembley showdown with Manchester City.
Arsenal goalkeeper Petr Cech has made a surprise return to Chelsea's training ground ahead of Sunday's big London derby after Adidas sent a consignment of gloves to his former club by mistake. Chelsea manager Guus Hiddink, whose misfiring champions travel to Cech's Premier League leaders on Sunday, made light of the situation at a news conference on Friday. "I was here when Petr showed up. It was nice to see him," the Dutchman told reporters at the Cobham facility to the south-west of London. "We had a chat here. Almost everyone was gone already, it was late afternoon....we tried to hide them, which he did not accept. Also we tried to make them a little bit slippery but he discovered that also. "They were wrongly sent here and we gave them back. It was nice. That's the story."
Chelsea manager Antonio Conte was fuming at the final whistle after Pedro and Alvaro Morata were dismissed in extra time and two penalty appeals had been waved away, but the Premier League champions regained their composure to win the shootout 5-3.
The win allowed second-placed Liverpool to close the gap on league leaders Manchester City to two points.
IMAGES from the English Premier League matches played on Sunday
Departing captain John Terry led his Chelsea champions to a rip-roaring 4-3 victory over Watford on Monday, scoring the first goal on an evening of celebration, fireworks and streamers rather than vintage football at Stamford Bridge.
Chelsea play "ugly" football under Jose Mourinho and the Premier League's runaway leaders deserve to be branded as boring because of their refusal to attack teams, their former manager Ruud Gullit has said.
The victory, Chelsea's 28th of the season, put the long-time league leaders 10 points clear of second-placed Tottenham Hotspur, who have only three games left to play.
Nuggets of news coming from the English Premier League
However, cracks in the relationship surfaced this season as the team's form slumped, with the first signs appearing as early as August when Mourinho hauled Terry off at halftime during a 3-0 defeat to ManchesterCity.
'If you are a big player, and paid like a big player, you must play like a big player and behave like a big player'
Jose Mourinho believes his Chelsea team could challenge for the Champions League this season despite their woeful form in the Premier League.
Chelsea will have to be wary of the danger posed by the in-form Marouane Fellaini.
Factbox on Jose Mourinho, who was named manager of Tottenham Hotspur on Wednesday
Images from the EPL matches played on Sunday
Chelsea skipper John Terry has hit back at Zlatan Ibrahimovic's description of his team mates as 'babies'.
Chelsea's players must look at themselves and start performing, former Blues stalwart Frank Lampard said as speculation continues to swirl over the future of manager Jose Mourinho.
Philippe Coutinho scored twice as Liverpool recovered from an early deficit to beat struggling Premier League champions Chelsea 3-1 at Stamford Bridge on Saturday and pile more pressure on Blues manager Jose Mourinho.
News of all that's transpired on and off the football field.
Tottenham moved up to seventh place with 36 points from 22 games
'I would like to make clear on behalf of everyone at the club our disgust with regards to the incident that took place on the Paris subway' 'We are proud to support the work of Kick it Out and Show Racism the Red Card among other organisations'
"I cannot understand what the official behind the goal does because he doesn't make a clear decision too."
Claudio Ranieri re-named himself The Thinkerman on Thursday as he reflected on masterminding Leicester City's improbable rise from relegation candidates to Premier League champions.
Manchester City's eight point advantage after 11 games is leading to talk of the Premier League title race being over in November, but as Manchester United manager Jose Mourinho noted - English football has a habit of throwing up surprises.
Jose Mourinho was delighted that Chelsea made a winning start to their Champions League campaign on Wednesday, but said he was not happy that Manchester United, Manchester City and Arsenal had all lost their opening matches.