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On a night when on-loan Tottenham Hotspur defender Eric Dier made his Bayern debut as a half-time substitute and England skipper Harry Kane saw a 23rd league goal of the campaign chalked off, Union coach Nenad Bjelica was sent to the stands after appearing to push Leroy Sane in the face, an offence which is certain to result in significant disciplinary action.

A 1-0 victory was the bare minimum in the wake of Sunday's (AEDT) home defeat by Werder Bremen with head coach Thomas Tuchel, who it was announced before kick-off has abandoned his pursuit of Newcastle United defender Kieran Trippier, reportedly under pressure after a testing run.

It took a double save by Union keeper Frederik Ronnow to keep the sides level when he first repelled Matthijs de Ligt’s header and then Dayot Upamecano’s follow-up from Joshua Kimmich’s sixth-minute corner.

Kingsley Coman saw an 11th-minute drive turned away and Konrad Laimer dragged another wide of the far post before De Ligt missed the target with another header from a corner as the home side pressed for an opener.

With Jamal Musiala and Sane prominent, Bayern probed away and Coman flicked just off target from a Guerreiro cross before Leon Goretzka curled another attempt over.

Kimmich shot tamely at Ronnow and Guerreiro fired another well wide with Union continuing to frustrate the hosts, although the visitors mounted a rare attack and Janik Haberer blazed over from distance after Robin Gosens had laid off Benedict Hollerbach’s cross.

Worryingly for Tuchel, Upamecano pulled up clutching his hamstring as he pursued Hollerbach, although the central defender managed to complete the half.

The sides headed for the dressing rooms to the clear displeasure of some of the locals at Allianz Arena with the deadlock unbroken, but with both Sane and Musiala having gone close in stoppage-time.

Dier belatedly replaced Upamecano at the break and the jeers turned to cheers within seconds when, after Kane’s shot had thundered back off the post, Guerreiro forced the ball past Ronnow at the second attempt to ease the tension inside the stadium.

Kane thought he had extended his side’s lead when he dispatched Sane’s 55th-minute cross, but his effort was ruled out for an offside all on Sane after a VAR review.

For all the home side’s dominance, Union remained in the game as long as only one goal separated the teams, and that jeopardy was highlighted when Kevin Behrens appeared to be tripped inside the box, but not in the opinion of the VAR official.

Tempers frayed on the sideline with 74 minutes gone when Bjelica raised a hand to Sane as the pair wrestled for the ball and received a red card for his actions.

Ronnow had to dive full-length to keep out Goretzka’s 81st-minute header, but the final whistle left many questions unanswered for Tuchel.