Arsène Wenger conceded that Arsenal are running on empty last night after a goalless draw at home to Fenerbahçe left them limping towards the first knockout round of the Champions League. Arsenal should still qualify because they require a single win from fixtures against Dynamo Kiev and Porto, but Wenger is concerned about his players’ lack of sharpness in a run of three matches without a victory — much their worst form of the season — before Saturday’s visit of Manchester United.

Sir Alex Ferguson’s side needed a late goal from Ryan Giggs to salvage a 1-1 draw away to Celtic, making it the first time for three years that the four English clubs had failed to register a win between them in a Champions League week, but it is Arsenal who approach the showdown with the Barclays Premier League champions with the greater problems as their players continue to drop like flies.

Manuel Almunia was left out against the Turkish side because of a stomach bug and Mikaël Silvestre suffered a suspected broken nose after being caught by Semih Sentürk’s elbow, joining a lengthy injury list featuring William Gallas, Emmanuel Adebayor, Emmanuel Eboué and Theo Walcott. To make matters worse, Robin van Persie starts a three-match suspension on Saturday. After claiming that Stoke City had set out to injure his players last weekend, Wenger was more relaxed on the subject of Silvestre’s bloodied nose, but the Arsenal manager was willing to own up to his side’s deficiencies.

“We had three or four clear-cut chances in the first half, but in the second half we dropped physically and were less dangerous,” Wenger said. “You expect Arsenal to create chances in the last 20 minutes and we didn’t do that because physically we lacked the resources.

“Man United drew, so I’m not too concerned. I will not tell you it’s not important, it’s a massive game for us. We play big games every three days, but Manchester United v Arsenal is always special. We know it’s vital to do well in the big games in this league.

“I don’t know if it was intentional [the injury to Silvestre], but he [Semih] rotated his arm and hit him on the nose. I didn’t see it well. I speak well when I see tackles afterwards on the video, but I couldn’t say if it was deliberate.”

A smattering of boos rang out as Arsenal left the field at the final whistle, but Cesc Fàbregas refused to offer fatigue as an excuse. “We know if we score one goal we will open teams up, but they come here to defend,” the midfield player said. “We won’t make any excuses. We know if we don’t play well there’ll be players waiting and ready to take the shirt. The next game against United is massive, which is welcome as the big players like playing in the big games.”

United were indebted to Giggs for the late goal that spared them from defeat and while they are not mathematically assured of a place in the last 16, Ferguson argued that they are home and dry, such is the unlikely permutation of results that would be needed to stop them. “We have qualified now and that’s the main thing, so we have no complaints,” he said.

With Celtic taking an early lead through Scott McDonald, Giggs’s 84th-minute goal came as a relief to Ferguson, who had rested Edwin van der Sar, Gary Neville, Patrice Evra, Wayne Rooney and Dimitar Berbatov in preparation for Saturday. Berbatov could have scored with the last kick of the match, but shot wide from eight yards.