THEO WALCOTT’S terrible run with injuries continues. The Arsenal winger limped off in the 33rd minute yesterday after a sliding challenge by Birmingham’s Liam Ridgewell and will have a scan to assess damage to a knee.

The Arsenal manager, Arsène Wenger, doubted that the England forward would play against AZ Alkmaar in the Champions League on Tuesday, but he added: “We will scan him tomorrow. Both knees are swollen, we don’t know how much of his pain is down to the kick and how much of his pain is down to a twisted ligament.

I don’t believe he will be available.” Wenger also criticised the tackle. He said: “It was a tackle which cut through, without restriction. I do not know whether he wanted to play the ball.”

Birmingham’s manager, Alex McLeish, defended his player. “It was a fierce defender’s tackle. Liam must have caught Walcott, but I don’t know whether it was dangerous. There was no free kick given. If you penalise every tackle it would be a different game.”

When Walcott went off, to be replaced by Andrey Arshavin, his side were two goals up and seemingly cantering to victory. Then an error by their second-choice goalkeeper, the young Italian Vito Mannone, put Birmingham back in the game. It began with a left-flank throw-in. Barry Ferguson looped the ball on, it struck Arsenal’s Abou Diaby on the back of the head and Mannone was challenged in the air by former Arsenal player Sebastian Larsson. The keeper could only push the ball out and Lee Bowyer shot home. Mannone protested in vain.

Birmingham began to believe they could leave the Emirates with something. Like Arsenal, they had only one man up, in the vigorous Cameron Jerome, but unlike the Gunners’ Robin van Persie, well-supported from midfield, Jerome was largely alone. He was committed, though, and often made use of the right wing, seldom wasting the balls that did come to him. It was a shame to see him forced off the field after 17 minutes of the second half. This meant that while Birmingham still resisted with some spirit, they no longer posed anything like a real threat to the Arsenal goal.

The home side took the lead after 16 minutes. Alex Song, who was influential throughout the match in central midfield, snapped up a ball and found Van Persie in an inside-left position. The Dutchman’s cross-shot sped low into the right corner.

Two minutes later Arsenal doubled their lead. Emmanuel Eboue found Tomas Rosicky, who had wandered over to the right, and his low cross eluded the defence and was easily exploited by Diaby on the far post.

That, it seemed, would be that, but then out of the blue came Birmingham’s goal and Arsenal, still playing by far the more attractive and inventive football, were no longer making the chances.

The exception was a moment in the 42nd minute when the irrepressible Arshavin suddenly made something out of nothing from an inside-left position but his shot was pushed away by Joe Hart, Birmingham’s goalkeeper.

Arshavin, always a delight with his dazzling feet and his capacity to do the unexpected, would ultimately score Arsenal’s third goal late in the game. He should not really have been allowed to. Stephen Carr, the visiting right-back, was nowhere near him when he got the ball on the left flank, calmly and coolly moved infield and placed his right-foot shot in the right corner.

There would have been a fourth goal when Van Persie served Eboue on the flank and Diaby met his brisk cross, but Hart saved.

Wenger was full of praise for midfielder Song. “He’s strong and smooth. He’s not rigid. He’s agile; a slalom player and not a straight line player. He’s a combination of strength and ability and I believe he uses his technique in a very intelligent way. Cameroon people are strong. You know in Africa they call them the Germans!”

Star man: Andrey Arshavin (Arsenal)

Yellow cards: Arsenal: Song Birmingham: Hart, Ridgewell

Referee: J Probert

Attendance: 60,082

ARSENAL: Mannone 6, Eboue 7 (Wilshere 90min), Gallas 6, Vernaelen 6, Gibbs 7, Diaby 7, Fabregas 6, Song 7, Walcott 7 (Arshavin 33min, 7), Van Persie 7, Rosicky 7 (Sagna 72min)

BIRMINGHAM: Hart 7, Carr 6, Ridgewell 6, R Johnson 6, Dann 7, Bowyer 7, Larsson 6, Ferguson 6, Carsley 6 (Phillips 79min) Jerome 7 (O'Connor 61min), McFadden 6 (McSheffrey 70min)