Robert Lewandowski continued his sparkling form with a hat-trick as Bayern Munich made a mockery of Dinamo Zagreb's 45-match unbeaten run with a 5-0 Champions League rout at the Allianz Arena.

Croatian champion Dinamo had not lost a competitive match since a 1-0 reverse to Astra in the Europea League last November and beat Arsenal in its Group F opener.

But the gulf in class was evident from the start of the match, with Lewandowski once more leading by example by making it 10 goals in his past three outings.

Pep Guardiola's side was rampant in the first half and raced into a 4-0 lead after 28 minutes, Lewandowski tapping in the second after Douglas Costa had opened the scoring.

A goalkeeping gaffe from Eduardo allowed Mario Gotze to get on the scoresheet, before Lewandowski doubled his tally from a Costa corner.

The Poland international then finished a fine move to complete his hat-trick after the break, as Bayern - which has won all seven of its Bundesliga matches this season - warmed up perfectly for Monday's (AEDT) clash with rival Borussia Dortmund.

Bayern monopolised possession in the opening stages and it was little surprise when it took the lead in the 13th minute.

Thiago Alcantara sprayed a brilliant ball to Costa on the left flank and the winger drove into the penalty before drilling his shot past the flatfooted Dinamo goalkeeper Eduardo at the near post.

The home fans were on their feet again eight minutes later.

A costly slip from Filip Benkovic allowed Thiago a clear run at goal, and the former Barcelona man showed impressive awareness to present Lewandowski with a tap-in.

Bayern capitalised from another Dinamo error in the 25th minute. Gotze played a neat one-two with Kingsley Coman and his shot looked easy enough for Eduardo to deal with, but the ball squirmed past the keeper.

Things worsened for the visitor when a rampant Bayern scored a third goal in the space of eight minutes.

Lewandowski was allowed a free run across the area and his side-footed shot from Costa's corner hit the underside of the crossbar and was judged to have crossed the line.

The domination continued after the break as Lewandowski grabbed his third in the 55th minute.

The former Dortmund star turned sharply on the edge of the box after collecting another fine Thiago pass before brilliantly lofting his shot past Eduardo.

Lewandowski nearly had a fourth but just failed to make contact with David Alaba's low cross, while Gotze saw an effort rebound off the outside of the left-hand post.

It stayed at five, though, as Bayern made it two wins from two in Group F.