Bayern Munich defender Mats Hummels has criticised RB Leipzig sporting director Ralf Rangnick for trying to influence the referee during Wednesday's DFB Pokal clash by presenting him with footage of a rescinded penalty at half-time.
Bayern edged past 10-man Leipzig on penalties after a 1-1 draw during a bad-tempered encounter at Red Bull Arena, with both sides expressing frustration with referee Felix Zwayer.
One of the turning points in the match came after 34 minutes when Zwayer rescinded a penalty decision in Leipzig's favour after Arturo Vidal had brought down Emil Forsberg. After consulting his assistant, who stood further away, Zwayer ruled that the foul had taken place outside the area and instead awarded a free kick.
At half-time, Rangnick stormed onto the pitch, trying to show Zwayer and his assistants video evidence of the incident on his smartphone. After some pushing and shouting, the Leipzig chief was sent to the stands for the remainder of the match.
"He can't just go to the referee with his mobile to show him the scene," Hummels, who tried to stop Rangnick at half-time, said on Sky in a postmatch interview. "I can't imagine that's allowed or wanted, otherwise the refs will constantly have club officials around them to show them scenes.
"I told Mr Rangnick that he should not do it, and that it's unsporting behaviour. I remained relatively calm. And it was not me who was sent to the stands."
Leipzig coach Ralph Hasenhuttl also criticised Rangnick's actions, saying: "You can't do that. It could lead to the ref thinking that he's not acting cool."
However, Hasenhuttl said he too was unhappy with Zwayer's performance, questioning the dismissal of midfielder Naby Keita for two bookable offences.
Having already been issued with a yellow card, Keita was sent off for the third time in only 39 days after a tactical foul on Robert Lewandowski, but Hasenhuttl felt it was the wrong call.
"For 55 minutes, it was a fantastic match. It was destroyed," Hasenhuttl said. "With a bit of tact you don't issue the second caution. He gets a yellow for his first foul [it was his fourth] ... gets fouled three times without any consequences."
Hasenhuttl also suggested the official had favoured Bayern, saying Zwayer's "double standards were hard to swallow," adding: "It's a fact that in such matches you just can't cope with those setbacks. It's already difficult enough to beat FC Bayern."
However, Bayern also had cause for complaint over Zwayer's performance, with Hummels saying he told the referee he was clearly trying to balance out the decisions he had made against Leipzig when awarding the hosts a penalty for a foul by Jerome Boateng.
"I told Mr Zwayer that it was the queen of concession decisions," Hummels said.