Ante Covic, in his first Bundesliga match as a head coach having been promoted from Hertha's reserve team, was on course for a memorable win, only for VAR to intervene when Grujic hauled Lewandowski to the ground.

It was still a stuttering start to the season for Bayern, though, who had looked to be in for an easy night after dominating early on.

Thiago Alcantara tested goalkeeper Rune Jarstein with a long shot from range after fine build-up play and Thomas Muller blazed narrowly wide as Bayern asked all the early questions.

Bayern appealed for a penalty when Lewandowski appeared to be barged over by Lukas Klunter as they broke following a Hertha mistake, but the referee felt it was shoulder to shoulder.

Vedad Ibisevic had a sight of goal at the other end, but stabbed his effort wide.

The opening goal, though, came from a predictable source in the 24th minute as Serge Gnabry was played in down the right and his low cross was perfect for Lewandowski, sliding in down the middle, to steer home.

Gnabry was denied by a smart stop at his near post by Jarstein moments later and Bayern should certainly have moved further ahead, Lewandowski guilty of a couple of weak finishes.

Instead, out of the blue, Hertha levelled.

Lukebakio, signed from the Hornets having spent last season on loan at Fortuna Dusseldorf, received the ball out on the left and cut inside and, as Bayern backed off, tried his luck. His shot hit the back of team-mate Ibisevic, who was looking in the other direction, and flew past a wrong-footed Manuel Neuer.

But worse was to come for the champions. Two minutes later Grujic flicked on a long punt forward from Jarstein and, despite a clash of heads with Benjamin Pavard in the aerial challenge, was able to run on to a perfectly-weighted through-ball from Ibisevic before rounding Neuer and tapping home to stun the Allianz Arena.

Grujic needed treatment on his head injury in the aftermath of the goal, but was fit to continue.

Kingsley Coman went down under very little contact from Niklas Stark at the end of the first half and Bayern's frustrations were clear as they demanded a penalty.

Bayern started the second half with intent, but their final passes were not coming off.

They were gifted a way back into the match on the hour mark as Grujic went from hero to villain.

There was no danger as the Serbian wrestled Lewandowski to the ground off the ball in the area, with the referee pointing to the spot after watching replays of the incident.

The Pole nervelessly sent Jarstein the wrong way with the penalty.

Bayern kept pressing for a winner, but Hertha stood firm, riding their luck at times, to hold on for a point.