Bayern Munich and Atletico Madrid made it four away wins from the opening four Champions League last-16 first leg matches when they triumphed at Arsenal and AC Milan respectively on Wednesday.
Toni Kroos opened the scoring in London for Pep Guardiola's side when he curled a stunning right-foot shot into the top corner in the 54th minute.
Second-half substitute Thomas Mueller headed the second goal for Bayern in the 88th minute following a cross from Philipp Lahm.
An incident-packed first half yielded two missed penalties and a sending-off.
Arsenal playmaker Mesut Ozil's weak spot kick was easily palmed away by Manuel Neuer in the eighth minute and Bayern's David Alaba smacked his penalty against a post after keeper Wojciech Szczesny was dismissed for bringing down Arjen Robben in the area.
At the San Siro, striker Diego Costa secured victory for Atletico when his powerful header nestled in the net with seven minutes to go.
On Tuesday night, Barcelona won 2-0 at ManchesterCity while Paris St Germain romped to a 4-0 victory at Bayer Leverkusen.
The other four first-leg ties will be staged next week.
Image: Toni Kroos of Bayern Munich celebrates scoring the opening goal with teammates Javi Martinez and Arjen Robben during the UEFA Champions League Round of 16 first leg match against Arsenal at Emirates Stadium in London on Wednesday
Photograph: Shaun Botterill/Getty Images
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