Chelsea threw two precious Champions League points away on Tuesday, missing a penalty and producing a lacklustre performance as they allowed Racing Genk to pull back from a goal down to draw 1-1.
Arsenal squandered their chance to qualify for the last 16 of the Champions League with two matches to play when they laboured to a 0-0 draw with Olympique Marseille in a dour Group F match at the Emirates Stadium on Tuesday.
Lionel Messi netted a hat-trick including his 200th goal for Barcelona in a resounding 4-0 victory at 10-man Viktoria Plzen on Tuesday that put the rampant Champions League holders through to the last 16.
AC Milan and Barcelona can wrap up their Champions League group with two matches to spare and reduce their much-anticipated meeting next month to a mere friendly if both win their respective games on Tuesday.
Bayern Munich defender Jerome Boateng was banned for two league games on Monday after being dismissed in their 2-1 defeat by Hanover 96 on Sunday and despite efforts by his club to help him escape a suspension.
Substitute Aaron Ramsey struck in stoppage time to secure Arsenal a 1-0 victory at Olympique Marseille in an uninspiring Champions League Group F encounter on Wednesday.
A Fernando Torres double helped the hosts record their biggest ever home win in the UEFA Champions League and consolidated their lead at the Group E summit.
Olympiakos got their first points in Champions League Group F by comfortably beating Borussia Dortmund 3-1 at the Georgios Karaiskakis Stadium on Wednesday.