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Barca trounced Levski Sofia on matchday one in Group A but travel to Bremen knowing Werder need to bounce back from their defeat to Chelsea.
Jose Mourinho's Premiership champions are in Sofia with captain John Terry expected to shrug off a back problem.
Group B sees arguably the match of the night in Milan as Inter take on Bayern at the Giueseppe Meazza.
Sporting are at Spartak Moscow in the other fixture in the group, in an early kick-off - 18.30 CET.
Liverpool entertain Galatasaray while Bordeaux meet PSV Eindhoven in Group C. Rafa Benitez has pledged to continue to rotate his squad as the 2005 winners take on a team from the scene of their penalties win against Milan.
The other two games are Shakhtar Donetsk versus Olympiacos and Valencia against Roma. The Mestalla meeting between Quique Sanchez Flores's highly-fancied Valencia and Italian giants Roma should be a mouthwatering tie.
You can follow every match with LIVE text commentary and up-to-the-minute details on Eurosport.com.