Bundesliga team Leverkusen turned a 0-1 deficit within four minutes to win 2-1 thanks to the winner by midfielder Sidney Sam in front of the home crowd at group stage of UEFA Champions League on Wednesday.
The Catalan giants dominated, mustering 17 shots to Plzen's none, but had only Andrés Iniesta's early goal to show for it until David Villa's late strike.
Manchester City cut it fine to keep their Champions League ambitions on track on Tuesday with substitute Sergio Aguero scoring deep in stoppage time to give them a dramatic 2-1 win at home to Villarreal in Group A.
Olympique Marseille and Arsenal look to put their mediocre domestic form behind them as they gear up for a potentially decisive Champions League clash at the Stade Velodrome on Wednesday.
Bayer Leverkusen look for their first win in eight attempts against a Spanish team when they entertain Valencia in a Champions League Group E tie on Wednesday.
Wayne Rooney converted two second-half penalties to give Manchester United their first victory in Champions League Group C with a nervous 2-0 success at Romanian debutants Otelul Galati on Tuesday.
Real Madrid continued to make smooth progress towards the knockout stages after a comfortable victory against Olympique Lyonnais maintained their 100% start to Group D
FC Barcelona will take a big step towards qualifying for the knockout stage of the Champions League when they entertain Czech side Viktoria Plzen in the Camp Nou on Wednesday night.