Thomas Muller has laid down the gauntlet to former team-mate Robert Lewandowski as the pair prepare to face off at Camp Nou.
Lewandowski left Bayern Munich for Barcelona over the summer, having scored 50 goals in his final season in Germany.
The Polish striker was supposed to help make Barca contenders for the Champions League trophy, but defeat on Wednesday would consign them to the Europa League despite their new number nine going into the game as the competition's joint-highest scorer.
