The Bavarians, who returned to winning ways after drawing their last two league games, are on 63 points, seven ahead of second-placed Borussia Dortmund, in action against Cologne on Sunday, with seven games remaining after the weekend.

Chasing a record-extending 10th league crown in a row, Bayern took the lead in the 16th minute when Union keeper Andreas Luthe was surprised by a Kingsley Coman shot from outside the box.

Tanguy Nianzou powered in a header in the 25th, and Lewandowski converted a stoppage time penalty to go in three goals up at the break.

The Pole added his second two minutes after the restart to take his league tally to 31 goals this season before the hosts eased off to take much of the pace out of the game.

Bayern also set a new league record having scored 81 goals by the 27th matchday.