Julian Nagelsmann claims Jude Bellingham tarnished Bayern Munich's Klassiker win over Borussia Dortmund with his costly outburst against the match referee.

Bellingham was unhappy after Dortmund were denied two spot-kicks in Saturday's action-packed Bundesliga clash prior to Mats Hummels being penalised for handball.

Robert Lewandowski converted the resulting penalty to earn Bayern a 3-2 win, leading Dortmund teenager Bellingham to question the integrity of referee Felix Zwayer in his post-game interview.

The England international appeared to allude to a six-month ban handed to Zwayer following a 2005 match-fixing scandal, which centred around fellow official Robert Hoyzer.

Hoyzer was found to have fixed 2. Bundesliga matches in 2004-05. One of those involved Zwayer operating as an assistant, with the allegation he took a €300 bribe. Zwayer strenuously denied any such wrongdoing in the course of that investigation.

Bellingham's comments are reportedly being examined by police, while the German Football Association (DFB) has fined the youngster €40,000.

As the fallout continues from Bayern's win, which moved them four points clear at the summit, Nagelsmann gave his view on the refereeing decisions and Bellingham's remarks.

"Those comments tarnished the game a bit," Bayern head coach Nagelsmann said at a news conference ahead of Wednesday's Champions League clash with Barcelona.

"I can understand the discussions. But the incident involving Marco Reus couldn't have resulted in a penalty because there was an offside.

"I wouldn't have complained about the penalty for us if it hadn't been given. I can understand from Dortmund's point of view."

Bayern now switch focus to the visit of Barca to the Allianz Arena, with the game to be held behind closed doors due to rising coronavirus cases in Bavaria.

The German giants have won each of their last three meetings with Barcelona, which is the longest run of wins by a team against Barca in their European Cup and Champions League history.

Nagelsmann's side are already assured of top spot in Group E, while the visitors may need to win if they are to progress, depending on how Benfica get on against Dynamo Kiev.

Despite Barcelona enduring a trying time on and off the field in recent times, Nagelsmann insists it is only a matter of time before the LaLiga heavyweights turn things around.

"I think they are still an extremely attractive club for players and fans," Nagelsmann said. "The financial figures are known. If that hovers over you, you will be a little inhibited.

"In a successful era you may become lazy and need too long for decisions. Then you seldom think about what happens when things go bad.

"The spitting out of talent has been a bit lacking, but that will only come again. Obviously they are making ends meet and still have a good squad.

"For me, Frenkie de Jong is one of the best midfielders in the world. They still have world-class players. They are under pressure in the table and have to win. They will give everything to make this a good game."

Bayern have won all five of their group matches, scoring a combined 19 goals and conceding three.

At home, they have scored five goals in each of their two Champions League games so far this term and have netted at least twice in each of their last 11 home matches in the competition.

The Bavarians will remain without Leon Goretzka on Wednesday due to injury, despite the midfielder returning to training, while Serge Gnabry is out with an adductor issue.

Despite having little to play for on the face of it, Nagelsmann intends to name a strong side to face Barca.

"We'll play our best available team," he said. "Benfica don't have to worry! We are going for six wins from six and that is a worthwhile goal."

Der Klassiker referee Felix Zwayer explained the controversial moments in Bayern Munich's 3-2 win over Bundesliga rivals Borussia Dortmund.

Dortmund succumbed to defeat at home to defending champions and leaders Bayern, with the second half seeing controversial decisions go in favour of Die Roten.

Firstly, Marco Reus' protests were ignored when the Dortmund man was tripped in the Bayern box by Lucas Hernandez, before the visitors got their winner in similarly contentious fashion.

Mats Hummels threw himself between two players in an attempt to reach a corner delivery, but he appeared to start stumbling and ultimately fell into the ball with his arm first.

While replays showed Hummels was not looking at the ball, seemingly rendering it accidental, Zwayer pointed to the spot following a VAR check and Robert Lewandowski subsequently scored what proved to be the winning goal.

Zwayer offered an insight into his decisions, telling Sky Germany: "It was contact in the upper body area, which is allowed to happen even at high speed.

"The situation is not black and white, I decided against the penalty kick because of my line [of sight]. It was not necessary for me because I had a clear view.

"Again, in the situation with the handball on Hummels I had a factual perception. In the other situation I had a complete view, if the video assistant had a second shot - like an arm that was out - he would have given me that on the ear."

On the Hummels incident, Zwayer added: "The situation was a standard, corner kick. I see in the running game that it's about a touch by Hummels. In the game it was not clear whether the arm went to the ball.

"I checked it after Cologne, then the arm position was checked. In the end, he clearly deflected the ball with his elbow. I came to the decision in the end that it was a penalty."

It comes after Dortmund star Jude Bellingham questioned the integrity of Zwayer in a remarkable post-match rant.

Bellingham suggested it was the standard of refereeing to be expected from someone who had "match-fixed" before, alluding to controversy earlier in Zwayer's career.

However, Zwayer has never been found to have fixed a game.

In 2005, Zwayer was caught up in a scandal that centred around fellow referee Robert Hoyzer, who was found to have fixed 2.Bundesliga matches.

In one match, Zwayer was Hoyzer's assistant and was accused of taking a €300 bribe before he and three others turned Hoyzer in.

Zwayer faced a German FA (DFB) disciplinary over the matter in 2006. In December 2014, German newspaper Die Zeit published documents that showed Zwayer was banned for six months, information that did not emerge at the time.

Dortmund head coach Marco Rose was sent off after BVB conceded a penalty to Bayern on Saturday.

Having lost their last four matches at home to Bayern – their joint longest losing streak at home to a team, Dortmund are second and four points off the pace through 14 matches.

"The first one [penalty], I still see it the same way. It would be a shame if we talk too much about refereeing decisions here now," Rose told reporters. "I saw both situations again, and now I can be accused, rightly of course, of wearing black and yellow glasses. But, for me, the situation with Marco Reus is different. Because Marco is clearly in front of the ball, the opponent not only pushes him from behind as the referee said and perceived, but he also runs him over.

"And there is also frustration. You can see that in the way he falls. And so, for me, it is a clear penalty. And I have seen the second situation several times. It starts with Thomas Muller's hand on Mats Hummels' shoulder. Mats tries to protect himself a bit, which is natural, which is very natural, stumbles, doesn't see the ball anymore, dives somewhere and then the ball falls on his hand. In the first situation there was no video evidence.

"The referee even said that he had received confirmation from Cologne that his perception was correct. This statement is incredible and not very comprehensible to me. And then, in the second situation, you look at yourself accordingly just with pity and bitterness. We have to talk about it very, very much. And of course, it also makes you emotional, that's clear."