Bayern Munich's Robert Lewandowski and Thomas Mueller celebrate after the match. Photo: Thilo Schmuelgen/Reuters

BERLIN – Bayern Munich reached the German Cup final by thrashing Bayer Leverkusen 6-2 away thanks to a Thomas Mueller hat trick after an early Robert Lewandowski double on Tuesday to stay on track for a treble of titles this season.

Bundesliga champions Bayern, who face Real Madrid in the Champions League semi-finals next week, enjoyed a sensational start and completely overran their opponents, scoring twice through Lewandowski in the opening nine minutes.

The Poland forward flicked in a powerful Javi Martinez shot to put the visitors ahead in the third minute, and then added another goal with a fine volley from a Franck Ribery cross.

Leverkusen pulled a goal back in the 16th with a Lars Bender header and came agonisingly close to levelling minutes after the restart as they battled to get back into the match.

But the home side’s hopes of a comeback were short-lived as Thiago Alcantara picked out Mueller to score Bayern’s third, and the Spain international slotted in the fifth after Mueller had scored again from close range.

The Germany forward completed his hat trick in the 78th after Leverkusen substitute Leon Bailey had pulled another goal back for the hosts with a whipped free kick.

Bayern, who won the treble in 2013, will face the winners of Wednesday’s semi-final between Eintracht Frankfurt and Schalke 04 in the final in Berlin on May 19.