With Barca, Xavi has won three Champions League crowns, eight La Liga titles and a host of other trophies.
Lionel Messi scored 41 goals in 37 La Liga appearances this term.
Real Madrid will finish runner-up despite Cristiano Ronaldo scoring a hat trick in a 4-1 win at Espanyol.
Guardiola said he hopes Barcelona win their first European title since 2011.
Bayern struck back with second-half goals from Lewandowski and Mueller but it was a case of too little too late.
Barcelona have the 3-goal advantage going into the second leg at Allianz Arena on Tuesday.
Bayern goalie Neur was earlier quoted in an interview saying that he would show Messi who the boss is.
It was the first time Getafe, who are 13th, have conceded five goals in the first half of a La Liga match.
Lionel Messi scores his 400th goal for Barcelona in hard-fought win over Valencia.
Neymar scored a brace while Suarez chipped in with a goal against PSG.
Real Madrid’s 3-0 win over Eibar earlier in the day means the European champions now trail Barca by just two points.
The contest also highlighted the gulf that has opened up between Spanish and English football in club football.
Lionel Messi moved ahead of Cristiano Ronaldo in scoring charts as Barcelona won 2-0 at Eibar to stay top.
Lionel Messi scored a record-setting hat trick to help Barcelona rout Rayo Vallecano 6-1.
Barcelona beat Villarreal 6-2 on aggregate while Athletic Bilbao beat Espanyol 3-1 on aggregate.