Graphic: five ways for United to finish off Arsenal at the Emirates

As a late-developing goalkeeper who spends his spare time studying the history of warfare, Manuel Almunia has always been a man apart in the Arsenal dressing-room, a status that is likely to be further enhanced when his colleagues read his comments this morning.

If not quite on the scale of a Roy Keane outburst, or even one from William Gallas, the Arsenal goalkeeper let rip at his team-mates’ performance during Wednesday’s 1-0 defeat by Manchester United.

Without Almunia, who made four outstanding saves as the home side rampaged forward in the Champions League semi-final first leg against seemingly star-struck opponents, United would already have all but qualified for the final in Rome, so he is entitled to voice his opinion. The Spaniard is renowned for his honesty and did not hold back, arguing that many of the Arsenal players cracked under the pressure and played as if they were lost on the biggest stage.

“I was disappointed with the performance,” Almunia said. “After the first 25 minutes we switched off and didn’t keep the ball as well as we should and know how to do. We were disappointed in the dressing-room. It was a lost game, nobody likes to lose, but after a few minutes you realise that Old Trafford is a very difficult place to win and keep a clean sheet.

“We were surprised at how they played, but some of our players were maybe lost at the beginning. That’s normal, it’s a big competition, it’s a big semi-final and you expect a lot of pressure on the players. I don’t know how every player felt inside, but it’s a big pressure on everybody. I still think we should have the experience to face these sort of games.

“Everybody was looking forward to this game for such a long time and you put everything into the game on the pitch and sometimes your head doesn’t respond enough to your desire. I hope on Tuesday [in the second leg] that everybody is focused on what we have to do, otherwise we will be lost.”

Despite his damning verdict, Almunia is adamant that Arsenal have what it takes to overturn the 1-0 deficit next week. The 31-year-old conceded that United are a better side than Arsenal, but believes that his team-mates can make up for their deficiencies through sheer force of will, a view shared by Arsène Wenger, their manager.

“Maybe Manchester United are stronger than us, but in terms of desire nobody can beat us,” Almunia said. “That’s what we have to do at the Emirates. We have to show our desire to win because this is the only trophy that we have left this season. Arsenal also know very well how to play football but if you don’t play in these sort of games, you are lost. We have the experience and have been showing in the league that we’re mature enough to win every game. On Tuesday, we will show we are good enough to win in the Champions League.”

Arsenal can take heart from having beaten United on their previous visit to the Emirates Stadium in November, with Samir Nasri scoring both goals in a 2-1 victory. “We showed that in the league, by beating them, that we can do it for sure,” Cesc Fàbregas, the Arsenal captain, said. “The tie is still open and in the Champions League we have seen worse things than that.

“We need to be more clinical in front of goal. That’s what we definitely have to improve because now we know for sure that we have to score.”

Wenger will rest several players for tomorrow’s Barclays Premier League match away to Portsmouth, with Mikaël Silvestre and Eduardo da Silva ruled out by groin injuries.