Lionel Messi scored a hat-trick as Barcelona opened their Champions League campaign with a dominant 4-0 win over Ajax yesterday.
It was a different story for Josť Mourinho, though, as Chelsea made a losing start for the first time when Basel came from behind to win 2-1 in London and add to the difficulties of the 'Special One' during his Stamford Bridge homecoming.
Last season's runner-up, Borussia Dortmund, also had a bad night, losing 2-1 at Napoli, with both coach Juergen Klopp and goalkeeper Roman Weidenfeller being sent off.
Seven-time champions AC Milan struggled, too, before two late goals gave the injury-hit Rossoneri a 2-0 victory at home to Celtic.
Meanwhile, Theo Walcott and Aaron Ramsey scored as Arsenal opened their 16th straight campaign in the top European competition with a 2-1 win at Marseille to join Napoli atop Group F.
Elsewhere, it was Atletico Madrid, 3, Zenit St Petersburg, 1; Schalke, 3, Steaua Bucharest, 0; and Austria Vienna, 0, Porto, 1.
At the Camp Nou, Messi scored his 60th, 61st and 62nd career goals in his 80th Champions League match.
Messi, the four-time FIFA world player of the year, opened the scoring in the 22nd minute after he was fouled, then fired a perfectly placed free kick.