Lionel Messi marked his first start after injury with a goal in Barcelona’s 1-1 draw at AC Milan in the Champions League on Tuesday while Fernando Torres got two as Chelsea thumped Schalke and Atletico Madrid’s charge continued.
Robert Lewandowski got the 82nd-minute winner as Borussia Dortmund put the brakes on Arsenal’s campaign with a 2-1 win in London that, along with Napoli’s 2-1 victory at Olympique Marseille, put three teams on six points in Group F.
Had Arsenal won, manager Arsene Wenger would have had a reason to celebrate his 64th birthday.
In Group E, Chelsea moved level on six points with Schalke 04 at the top with a 3-0 win in Germany where Torres celebrated his 100th start for the club with the fifth-minute opener and another after 69 minutes before Eden Hazard added a late goal.
The top two are clear of third-placed Basel, who have four points ahead of Steaua Bucharest on one after those two teams shared the spoils in a 1-1 draw in Romania.
Celtic got their first points in Group H after a James Forrest penalty on the stroke of halftime and a deflected shot by Beram Kayal early in the second half helped them to a 2-1 win over Ajax Amsterdam, who got a consolation in added time.
The glamour match at the San Siro where seven-times European champions Milan hosted four-times winners Barcelona fizzled out in the second half after a frantic opening period of pressure from the Italians.
Milan took an early lead through Robinho following a smart exchange with Kaka after nine minutes but with Barca then dominating possession, it was a matter of time before they made it count.
Andres Iniesta found Messi, who was making his first start after a three-week layoff, in space on the right and the Argentine kept his cool under pressure from Kevin Constant and Riccardo Montolivo to find the bottom right corner to equalise.
“We lost two points... because we created more goal chances and for this reason we deserved a victory,” said Barcelona coach Gerardo Martino, whose side, like Milan, remain unbeaten in the group.