MUNICH -- Thomas Mueller scored two goals as Bayern Munich dominated Barcelona on Tuesday to take a commanding 4-0 lead after the first leg of their highly anticipated Champions League semifinal.
Mueller scored in the first half and added another after Mario Gomez and Arjen Robben had also scored in the second half. It was Barcelona's biggest loss in the Champions League since 1997, and a humbling defeat for the team that has been widely regarded as the best in the world for the last five years.
"The team is fantastic, I haven't experienced such a night in my life and I've been around for a while," Bayern chairman Karl-Heinz Rummenigge said.
"We knew we were able to give them a good competition," Robben said. "This team (Barcelona) has dominated Europe over the last five years and if you beat them like this, I think you can be proud."
Lionel Messi started for Barcelona despite injury worries but looked far from his best and was hardly a factor in the match. Barcelona had few chances, while Bayern used its size to outmuscle the Spanish side on set pieces.
Bayern showed its attacking intent from the start and took less than two minutes to produce the first opportunity of the match when Javi Martinez sent a backheel pass to Arjen Robben, but the winger's shot was saved by goalkeeper Victor Valdes.
The German champion had calls for a penalty declined in the 15th when the ball appeared to hit Gerard Pique's arm after a corner from Robben.
But Bayern scored after another corner, from Franck Ribery. The ball rolled to the far post, here Robben crossed to Dante. The defender headed back across the goal and Mueller raced to head it in. Valdes got his hands on it but could not prevent the ball from sliding into the net.
Barcelona kept possession more than Bayern but was unable to break through its crowded defense until the 29th, when Dante was just a step ahead of Messi to clear a cross from Pedro Rodriguez.
Another Bayern corner produced calls for another penalty as the ball seemed to touch Alexis Sanchez' arm when he challenged Dante in the air but the whistle stayed silent.
Moments later, Gomez was booked for upending Messi and young defender Marc Bartra also got a yellow card for a tackle on Mueller. Bartra got a chance to play because two of Barcelona's defenders, Carles Puyol and Javier Mascherano, are injured.
The second Bayern goal also came after a corner, with Mueller at the far post rising over Daniel Alves and heading across the goal for Gomez to knock in from close range, although he might have been slightly offside.
Bayern's third came as Robben went around Jordi Alba, who was blocked by Mueller as he tried to chase the Dutchman, who slotted the ball inside the right post.
Ribery and David Alaba did the work for Bayern's fourth, with Alaba swinging in a pass for Mueller to knock in from close range.
The loss equaled Barcelona's biggest in the Champions League, a 4-0 defeat to Dynamo Kiev in the group stage in 1997.
"We can be proud, we played a terrific game everybody," Robben said. "We fought for every meter and we didn't give them much space to play."
Messi injured his right hamstring on April 2 and has since been sidelined for three Spanish league games.
However, he went on as a substitute in the second half in the return leg against Paris Saint-Germain to help Barcelona come from behind and advance from the quarterfinals two weeks ago.
The four-time FIFA player of the year changed the momentum of that game, but he was shut down in Munich and did not look fit.
Barcelona's only chance in the second half was when Bartra was alone after a free kick, only to send the ball way high on the turn.
Bayern club president Uli Hoeness attended the match, as always wearing one of his red-and-white club scarves. Hoeness is under a tax evasion investigation, news that broke two days before the match and dominated German media coverage in the buildup.