Arsène Wenger accused the Italian referee Nicola Rizzoli of "killing" Arsenal in their 2-0 home defeat by Bayern Munich on a Champions League last-16 night when the Arsenal manager also admitted that Mesut Özil had failed a mental test.

The tie might have turned out differently had Özil not shot weakly at the Bayern goalkeeper Manuel Neuer from the penalty spot in the ninth minute. Wenger said that Özil's head went down thereafter.

Wenger raged at Rizzoli's decision to send off Wojciech Szczesny in the 38th minute, after the goalkeeper had brought down Arjen Robben inside the area. David Alaba missed the penalty for Bayern but Arsenal's 10 men were eventually worn down. It was highly debatable whether Robben had been denied a clear goalscoring opportunity by Szczesny.

Wenger poured out the frustration, as Arsenal confronted the prospect of a fourth consecutive last-16 exit and the picture he painted was one of helplessness. He had lost Kieran Gibbs to an injury on 31 minutes and, after introducing his substitute goalkeeper, Lukasz Fabianski, for Szczesny, he had little further room for manoeuvre. His Bayern counterpart, Pep Guardiola, by contrast made attacking tweaks and substitutions and his team finished as comfortable winners.

“The red card didn’t change the game, it killed the game,” Wenger said. “Until then it was top quality but in the second half it was boring for the neutrals. It was one-way traffic. The referee made a decision that killed the game. These rules are different in every country and in Italy you get sent off for these kind of fouls.

“Our keeper genuinely went for the ball, he touched Robben and he certainly made more of it. I told Robben that. He has enough experience to know to make more of it. Overall, I felt Bayern made more of every single contact.

“We had lost Gibbs, we lost a goalkeeper ... we made two changes and were down to 10 men. You cannot bring anyone else on in case anyone gets injured. You run after the ball and they bring fresh players on. I just feel frustrated. There was no game at all after half-time.”

Özil, who missed a less important penalty at home to Marseille in the group phase, held his head after his deliberate run-up failed to fox Neuer. Late on in the game he was berated by his teammate Mathieu Flamini for failing to track back. "He was affected by the penalty miss," Wenger said. "You could see, even five or 10 minutes later, he was still shaking his head. It had a huge impact on his performance. You are always concerned about the confidence of your players because that is your petrol in the team. It is what gives them the courage and desire to play.

“We needed that penalty tonight. You could see Bayern were on the ropes. We had three good chances in the first 15 minutes. And I feel to make them more insecure we needed to score that penalty but he missed it.”

Wenger said that he did not see Szczesny making an obscene gesture as he left the field while Bacary Sagna said that Robben did not spit at him during another flashpoint. “I don’t think so,” Sagna said. “It went well between us tonight.”

Michael Ballack, the former Bayern captain, said that Özil had not looked confident as he addressed his penalty and said that he "looks a bit lost in this team."

Ballack, working as a TV pundit at the game, added: “I was watching one situation where Flamini was moaning to him. It seems like Özil does not have the acceptance of his team. Also, Mertesacker two months ago, when he was shouting at him on the pitch [at Manchester City]. A player like him should be untouchable with his quality but it looks like he has not the acceptance.”

Pep Guardiola, the Bayern manager, for whom this was a first win at the Emirates, said that the penalty award and the red card were the correct decisions.

Wenger was left merely to maintain that the tie was not yet over and Arsenal would fight until the end. "It was a similar repetition to what happened at Manchester City [on Tuesday night against Barcelona] when they were down to 10 men," Wenger added. "We also conceded a goal in the last minute because maybe we wanted to score a goal from the free-kick and we got caught on the counter attack." Guardian Service