Bayern Munich's 4-0 rout of Barcelona in a Champions League semifinal first leg on Tuesday was partly down to two goals that should have been chalked off, said assistant coach Jordi Roura.

Mario Gomez looked marginally offside when he turned in Thomas Mueller's header from close range for the second goal in the 49th minute.

The two-goal Mueller also appeared to obstruct Jordi Alba when the fullback attempted to stop Arjen Robben as the Dutch international winger ran through to score Bayern's third after 73 minutes.