Defending champions Bayern Munich won 2-0 at 10-man Arsenal Wednesday in an eventful Champions League round of 16 first leg, while Atletico Madrid scored a late 1-0 win at AC Milan.

Bayern, who are keen to become the first team since Milan in 1990 to win back-to-back European titles, needed goalkeeper Manuel Neuer to save an early penalty from Arsenal’s Mesut Oezil, as the Gunners made an aggressive start at the Emirates Stadium.

Oezil had been awarded the penalty himself after being clumsily pulled down by Bayern defender Jerome Boateng.

The match swung on an incident in the 37th minute, when Arsenal goalkeeper Wojciech Szczesny was rather harshly sent off for pulling down Bayern’s Arjen Robben, a decision fiercely protested by the Arsenal fans and manager Arsene Wenger.

Bayern’s young left-back David Alaba hit the post with his spot-kick, but, with an extra man, the Munich team continued to dominate.

Toni Kroos broke the deadlock for the visitors in the 54th minute with a handsome long drive, after taking a pass from captain Philipp Lahm.

Man-of-the-match Lahm set up subersub Thomas Mueller to make it 2—0 with a precise header three minutes from time.

Meanwhile in San Siro, Atletico Madrid defended well against an AC Milan team guided by veteran playmaker Kaka, who hit the Spaniards’ crossbar in the 16th minute.

Milan then had a good penalty claim turned down when Andrea Poli was brought down by Raul Garcia.

Atletico gradually came out of their defensive shell in the second half, and silenced the crowd seven minutes from the end with what could prove to be a vital away goal.

Captain Gabi swung over a near-post corner, Milan’s Ignazio Abate recklessly headed across goal and Diego Costa headed home for the visitors at the far post.

It was possibly more than Atletico deserved, but their resilience, discipline, patience and opportunism had to be admired.

The second legs will be played March 11.

Tuesday’s games had started the pattern of away wins, with Paris Saint-Germain enjoying a 4-0 romp at Bayer Leverkusen and Barcelona winning 2-0 at Manchester City.

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