Hansi Flick lauded in-form striker Robert Lewandowski as he bids to challenge Lionel Messi for the Ballon d'Or, but the Bayern Munich coach questioned why Philipp Lahm had never won the award.

Lewandowski continued a sensational start to the 2019-20 season with four goals in a 6-0 win at Red Star Belgrade in the Champions League in midweek.

That haul took the Poland international, nominated for the Ballon d'Or, to 27 goals in just 20 appearances since the beginning of the campaign.

But while Flick considered the merits of Lewandowski and Barcelona superstar Messi, he took the opportunity to address Lahm's failure to claim world football's top individual prize in a glittering career.

Former Bayern full-back-turned-midfielder Lahm won eight Bundesliga titles, one Champions League and the 2014 World Cup, yet he ranked only as high as sixth after Germany's triumph in Brazil.

"Lewandowski and Messi are exceptional players," said Flick.

"[Lewandowski] is one of the most complete strikers around, if not the best number nine in the world. He has everything you need up front.

"He can head the ball, finish and hold it up. His work off the ball is important for the team.

"But I do not understand why a player like Philipp Lahm never won the Ballon d'Or. He won everything [as a team player]."

Bayern, third in the Bundesliga, a point behind leaders Borussia Monchengladbach, face Bayer Leverkusen on Saturday.

"We are still one point behind, so we have to rely on others as well," Flick said. "It is important that everyone gives everything and puts their quality at the service of the team."