Beware the wounded animal. Humiliation does not rest easy with Arsenal and, after the 4-0 FA Cup fifth-round defeat by Manchester United on Saturday, it is time for pay-back. That it is AC Milan up next does not faze Arsène Wenger and Cesc Fàbregas one iota. The top Gunners came out firing yesterday.

Arsenal face Milan, the Champions League holders, in the first leg of their first knockout round tie at the Emirates Stadium tonight. For Wenger, the manager, and Fàbregas, the Spain midfield player, it is an opportunity to erase quickly the demons from Old Trafford. And one day, Fàbregas believes, Arsenal could even usurp Milan as the leading team in Europe.

“Milan are maybe not doing too well in Serie A, but they are different in the Champions League,” Fàbregas said. “They have one of the strongest midfields in the world who work very hard for the team. If you let them think for one second more than normal, they will score. They can kill you in a second. But we are not scared of anything. We want to be like them one day in the future and we can show that we are ready.”

Fàbregas would like be at the Emirates when his vision of the future arrives. Despite reports to the contrary, he is not contemplating leaving and has a contract until 2014. “I can see myself for a long long time at Arsenal,” he said. “We have a young side here and it is very competitive. Everyone has to fight for their place, no one is secure, and that has to be good.”

Not that Fàbregas enjoyed a happy evening on Saturday. The hammering by United, albeit against a weakened Arsenal side, hurt deeply. It was a time for detailed reflection and a reevaluation of where he and his teammates were heading. “The result was a mistake,” he said. “Yes, Saturday night was very bad for me. I don’t think I moved from home; I was quiet, I was trying to work things out, what we did wrong. But sometimes you can draw positives from displays like that. You have to.”

A reaction, such as that of Fàbregas, is what Wenger is hoping for. When Arsenal lost 5-1 to Tottenham Hotspur in the second leg of their Carling Cup semi-final at White Hart Lane last month they responded with four successive victories, with 11 goals scored and only one conceded.

“Yes, the 4-0 was difficult to understand. It was surprising,” Wenger said. “But the players will bounce back, don’t you worry about that. They have that mental strength, the ambition, the quality.

“Sure, we were a bit quiet in training yesterday. When you have a big disappointment, sometimes you forget how good you are. But today, you could see that everyone was up for it again and had refocused.”

Wenger is aware of Milan’s threat. They may have several players of thirtysomething vintage but in Kaká, they have one of the world’s most lethal game-breakers. “This is the ultimate test,” Wenger said. “They are the champions and we are in the position of challengers. The target in front of us is so massive. We will have to be at our best, but we can beat them.

“The first leg will be decisive. Not mathematically but mentally. It can strengthen the belief in one side and weaken it in the other. That is crucial. We had a bad day at the office. Now, we will play without any handbrake.”

For Carlo Ancelotti, the Milan coach, defeat in North London would not unduly trouble him. “It is important to understand that we can always do it,” Ancelotti said. “We can always win the return match.”

— If, as expected, Valerio Fiori plays for AC Milan this evening, the combined ages of the starting goalkeepers will be 76. Jens Lehmann, of Arsenal, is also 38. Fiori, who will step up in the absence of the injured Dida and Zeljko Kalac, has played only two matches for Milan in eight seasons. “I’ve been training every day for 20 years so I should be ready,” Fiori, a law graduate from the University of Rome, said.