Robert Lewandowski's strike sent Bayern Munich back to the top of the Bundesliga but the European champions had to settle for a 1-1 draw at Union Berlin.

Grischa Promel's early header put Union in front at Stadion An der Alten Forsterei on Saturday, but they were unable to consign Bayern to what would have been a first defeat in 17 matches.

Lewandowski's 16th goal in as many games this season brought Hansi Flick's side level and neither team could force a winner in a pulsating contest.

The defending champions have now drawn three of their past four Bundesliga games but sit at the summit above RB Leipzig on goal difference.

Union stunned Bayern by taking the lead inside four minutes, Promel glancing Christopher Trimmel's inviting corner just inside the far post for his first goal since May 2019.

Taiwo Awoniyi spurned a glorious chance to double their lead when he dragged a left-foot finish just wide with only Manuel Neuer to beat after a mistake from Alphonso Davies.

Lewandowski wanted a penalty when he felt Marvin Friedrich had brought him down as he was about to pull the trigger and Andreas Luthe palmed away Serge Gnabry's rasping drive - Bayern's first shot on target - late in an entertaining first half, in which Union lost Marcus Ingvartsen to injury.

Luthe spread himself superbly to deny Kingsley Coman before Neuer had to be alert when Awoniyi was almost picked out by a clever ball over the top.

Sheraldo Becker dragged a shot wide as Union continued to pose a threat, but Lewandowski finished clinically first time from close to the penalty spot to level after Coman pulled the ball back following a great run down the left.

Keita Endo wasted a chance to put Union back in front and Luthe produced a great late reflex save to keep out Eric Maxim Choupo-Moting's late header as the two sides had to settle for a point.