Bayern Munich have every right to be frustrated by the manner of their Champions League exit at the hands of Real Madrid.

The German outfit, trailing 2-1 from the first leg, were in a great position to win the tie when an own goal by Sergio Ramos gave them a 2-1 lead in Tuesday’s return fixture at the Bernabeu.

But then Arturo Vidal was shown a harsh red card and the contest quickly fell away from Carlo Ancelotti’s side.

Bayern managed to take the game to extra-time but their task of holding out for penalties was made impossible by some poor decisions from referee Viktor Kassai and his assistants.

Cristiano Ronaldo scored two goals in the additional period but the Portuguese appeared to be offside for both.

Meanwhile, Madrid midfielder Casemiro was rather fortunate not to receive the same punishment as Vidal when, while on a yellow card, he went in late on Arjen Robben.

Vidal and Franck Ribery both took to social media after the match, which ended 4-2 to Real Madrid, to express their disappointment over Kassai’s game-changing decisions.

Kassai’s Wikipedia page was edited, too, to reflect how much he benefitted Madrid.

Bayern players were irate

Understandably, Bayern’s players were annoyed. There were reports that Vidal, Robert Lewandowski and Thiago Alcantara paid Kassai a visit in the referee’s dressing room after the game.

According to Marca, Thiago was particularly irate at full-time and spoke to Sergio Ramos and Florentino Perez in the tunnel.

How Perez calmed Thiago down

The ex-Barcelona player shares a good relationship with Perez, Madrid's president, through his father, former professional footballer Mazinho, and Perez managed to calm Thiago down by reminding him of the decision to award Bayern Munich a penalty in the first leg after Dani Carvajal was adjudged to have handled Ribery's shot inside the area.

'These things happen in football', was Perez's implied message.

Vidal missed the penalty

Not that Perez's words will have made Thiago feel any better, mind. Remember how that resulting penalty went? If not, here's a reminder.

Ancelotti: Kassai wasn't up to the task

After Tuesday's defeat, Ancelotti accused Kassai of not being "up to the task" of refereeing such a huge Champions League quarter-final.

"We had thought of everything going into this game - except the referee," Ancelotti said, via BBC Sport.

"You can't decide a semi-final spot like this. It shouldn't happen at this level. The referee probably wasn't up to the task.

"I don't think Real Madrid have any influence on referees. The officials simply got it wrong. I had never been in favour of video technology, but I must admit it's necessary now."

Were Bayern cheated out of victory - or would Madrid have gone on to win anyway? Let us know in the comments section below!