Bayern Munich romped to victory against Italian champions Juventus in the quarter-finals, and have already wrapped up their domestic title. It seems nigh-on impossible for Pep Guardiola to improve the Bavarian team when he will arrive next season, and he'll be keeping a keen eye on this fixture as his future side meets his former one.
The last time these teams met competitively was in the quarter-finals of this competition in 2009. Guardiola was still in charge of Barça, and Bayern fans won't want reminding of how the tie played out. The Catalans romped to a 4-0 victory at home before drawing 1-1 at the Allianz Arena, in a dominant 5-1 aggregate victory.
Barcelona haven't quite sealed La Liga yet, though Tito Vilanova's team are 13 points clear of Real Madrid, and will surely secure it in the next few games. Still, they've shown signs of infallibility recently, and only qualified for these semi-finals with a late goal against a disciplined Paris Saint-Germain.
Franck Ribéry. Clearly, when the best player in the world -- Lionel Messi -- will be involved, he's going to be important. But, just as key as how the Bayern defence deals with Leo, is how Barça's will deal with width. Against Paris Saint-Germain, Barcelona seemed to struggle with the quick counter-attacks and width provided by Lucas Moura, Ezequiel Lavezzi and co. With Ribéry expected to find some space in behind Dani Alves, he'll be vital in determining the outcome of this match.
Matchups to watch
David Alaba vs. Dani Alves - A young offensive left-back takes on an experienced offensive right-back. The battle down this flank could be crucial. With Alaba having winger Ribéry taking on more attacking duties ahead of him, he can afford to be a bit more conservative than Alves. Still being only 19, Alaba -- who scored in the quarter-final against Juventus -- will have to stay disciplined, and not let inexperience get the better of him.
Thomas Müller vs. Sergio Busquets - It is unfortunate that Bayern's usual central advanced playmaker Toni Kroos has been ruled out for the rest of the season through injury, though his teammate Thomas Müller represents a more than adequate stand-in. Müller's tendency to drift wide to link play means he'll prove to be a formidable opponent for Barça's defensive midfielder Sergio Busquets to stop.
Javi Martínez and Bastian Schweinsteiger vs. Lionel Messi - I couldn't ignore him any longer. Despite supposedly being injured for the game against PSG, Messi came off the bench in the second half and completely changed the match -- and was without even being greatly involved. The influence and impact he has on this Barcelona team was obvious, and how Bayern's deep midfield duo of Javi Martínez and Bastian Schweinsteiger deal with him will be key.
Bayern through by a goal - It is a tie which is almost impossible to predict. Doubtless these sides are the two most formidable in Europe this season, and trying to pick a winner is like splitting hairs. They both rely on an intense but disciplined pressing game, and the winner will be the more effective team in this area.
PSG harmed Barça with a much more conservative, counter-attacking strategy than Bayern are used to in the last round, and the Bavarians are unlikely to be happy sitting so deep as Carlo Ancelotti's side. However, they provide just as much of an attacking threat, and have a stronger midfield to boot. Their quick counter-attacking play will do damage, and I think they'll just squeeze through.