Barcelona have won the Champions League five times, most recently in 2015, and face a tough task to get back to the top table of European football after being forced to sell club legend Lionel Messi due to financial problems.
Robert Lewandowski struck the goal that sealed Poland's victory over Saudi Arabia on Saturday.
Undefeated since late December, Barca are the only team in Europe's top-five league who have yet to lose in 2025.
Striker Robert Lewandowski scored a first-half penalty to give Barcelona a hard-fought 1-0 home win over Rayo Vallecano.
Barcelona signing Robert Lewandowski is relishing a new challenge after joining the Catalan club and the 33-year-old said he was ready to play in their upcoming pre-season game against rivals Real Madrid in the United States.
The Polish striker will miss games against Espanyol, Atletico Madrid and Getafe when LaLiga resumes after the World Cup.
'Robert is an incredible player and he won everything with us. We are incredibly grateful to him.'
Lewandowski strike gives Barcelona 1-0 win over Alaves
Poland and Bayern Munich striker Robert Lewandowski hailed Barcelona coach Xavi as the main reason for his move to the La Liga club.
Real Madrid delivered manager Carlo Ancelotti and midfielder Luka Modric a victory in their final game at the Santiago Bernabeu on Saturday, with Kylian Mbappe scoring twice in a 2-0 win over Real Sociedad to end their LaLiga season.
He is the youngest player to debut and score for Spain and in LaLiga, the Champions League and the Euros. He also holds the records for youngest player in a Clasico and youngest scorer in both the Super Cup and Copa del Rey.
With Poland sure to rely just as heavily on Robert Lewandowski in their matches against Spain and Sweden, their hopes will rest on coach Paulo Sousa finding a system that better suits their top player.
Atletico Madrid clawed back from two goals down to rescue a last-gasp 4-4 draw at Barcelona in a rip-roaring battle in the first leg of their Copa del Rey semi-final on Tuesday.
Two of the most intimidating strikers in world football, Argentina's 35-year-old Lionel Messi and Poland's 34-year-old Robert Lewandowski, line up against each other on Wednesday with a last 16 place at stake in the World Cup.
Barcelona manager Hansi Flick was upset over several refereeing decisions in his side's 4-3 loss at Inter Milan that stopped the Catalans reaching their first Champions League final in a decade after an extra-time goal by home substitute Davide Frattesi.
A round-up of Tuesday's Champions League quarter-finals second leg between Barcelona and Dortmund, Aston Villa and Paris St Germain.
Barcelona returned to the top of the LaLiga table with a comfortable 4-0 home victory over 10-man Real Sociedad on Sunday.
'He is the world's best centre-forward and I hope he scores against Paris too.'
A summary of Saturday's action in LaLiga, Bundesliga and Serie A.
Saudi Arabia took third place in Group C and will feature in a fourth phase of qualifiers in October alongside Indonesia, Qatar, the United Arab Emirates, Iraq and Oman.
All the action from La Liga and Serie A matches played on Sunday.
LaLiga leaders Barcelona lost 1-0 to Leganes on Sunday
Iga Swiatek said she was "overwhelmed" after finding out Poland and Bayern Munich striker Robert Lewandowski was in attendance
Images from the Champions League semi-final first leg between Barcelona and Inter Milan at Estadi Olimpic Lluis Companys, Barcelona, Spain, on Wednesday.
Bayern Munich's Polish striker Robert Lewandowski won the FIFA Best Men's Player award for 2021 with Barcelona's Spanish midfielder Alexia Putellas winning the FIFA Best Women's Player prize at Monday's ceremony.
Robert Lewandowski broke Gerd Mueller's 49-year-old Bundesliga goal-scoring record
Nagelsmann said Lewandowski was still at a top level despite his 34 years and expected him to keep scoring an average of 40 goals a season. The striker has six LaLiga goals in five matches for Barca so far this season.
Bayern Munich forward Robert Lewandowski was named The Best FIFA Men's Player 2020 on Thursday, beating off competition from last year's winner Lionel Messi and Cristiano Ronaldo.
Barcelona came from an early goal down to beat Real Madrid 5-2 in the Spanish Super Cup final on Sunday
Barcelona snapped their four-match winless streak in LaLiga with an emphatic 7-1 victory over Valencia on Sunday.
Liverpool stuttered into the quarter-finals of the Champions League with a 2-1 aggregate win over Inter Milan after suffering a 1-0 loss to the Italian side, who were reduced to 10 men, at Anfield on Tuesday.
Barcelona's Robert Lewandowski scored a quick-fire second-half double to set the leaders on course for a thrashing of Real Madrid.
Champions Bayern Munich squandered a two-goal lead to end their season with a 2-2 draw at VfL Wolfsburg on Saturday but of more concern was confirmation that top striker Robert Lewandowski said he wanted to leave the club.
Kylian Mbappe bagged his first hat-trick for Real Madrid as the LaLiga champions easily beat bottom-club Real Valladolid 3-0 on Saturday
Barcelona will go to the international break on top of the standings on a perfect 12 points from four games, five ahead second-placed Villarreal and seven clear of bitter rivals Real Madrid
The Polish forward scored 15 goals on the way to Bayern Munich's sixth Champions League title, hitting the target in every match before the final except a group game against Tottenham Hotspur when he was rested.
A summary of Saturday's action in LaLiga, Serie A, Bundesliga and Ligue 1.
Robert Lewandowski and substitute Pablo Torre each scored twice to help leaders Barcelona thrash visitors Sevilla 5-1 in LaLiga on Sunday in a confidence boost for Hansi Flick's side ahead of key clashes against Bayern Munich and Real Madrid.
Poland's star striker Robert Lewandowski scored the winner to secure Poland a place at Euro 2016 with a 2-1 victory in Warsaw on Sunday.
Barca will now visit seventh-placed Osasuna on Saturday before hosting Young Boys in the Champions League next week, when they will look to rebound following a 2-1 loss in their opening match at Monaco.