The Gunners had gone into the day at the top of the Barclays Premier League, but failed to secure victory in front of their own fans as Alex McLeish's men produced a battling display to earn a share of the spoils.

Everything looked to be going to plan when Emmanuel Adebayor's penalty put Arsenal ahead after 21 minutes after Stephen Taylor was adjudged to have brought down Eduardo from behind.

However, Birmingham were level just after the restart through Garry O'Connor's deflected header following a corner, and the visitors held on under immense late pressure to boost their own confidence of staying in the top flight.

Wenger accepted his side - whose only other failure to win at home in the Premier League came against Manchester United, which ended 2-2 - were below par.

"It was very frustrating," said the Arsenal boss.

"The crowd pushed us on, but we were punished for losing concentration on the set-piece.

"We thought it was going to be too easy, but we didn't create enough overall.

"We were not sharp enough and they defended well. It's as simple as that."

Wenger added: "Every game is important so it's hard to say which is the crucial month, but today we lost two points we shouldn't have lost.

"I'm confident the team will re-focus because they are very disappointed. The focus today wasn't good enough."

Arsenal were missing the likes of Robin van Persie and Tomas Rosicky this afternoon, both of whom had a virus.

Kolo Toure, Emmanuel Eboue and Alex Song are all away at the African Nations Cup.

Wenger, though, refuted suggestions his squad was in need of reinforcements.

"I don't look for anybody," insisted the Arsenal manager.

"The last excuse you should look for when a team that has won many games this season doesn't win is to say you should buy players."

Wenger maintained: "I don't think we missed Kolo either: Philippe [Senderos] wasn't involved in the set-piece for the goal.

"We just didn't defend it well and that's how we were punished."

Blues manager McLeish, meanwhile, was full of praise for his battling side, who were lead by captain Damien Johnson - playing with a protective mask two weeks after suffering a slight skull fracture.

"We were playing against a special team and the determination of the players got us through," said the former Scotland manager.

"Arsenal can go through you like a hot knife through butter - but we had to concentrate for 90 minutes.

"We broke them up a few times and defended very well. They sniffed the danger and snuffed out the dangers most of the time."

McLeish feels with a few extra bodies, Birmingham can prove a match for most sides in the top flight, rather than just be battling for survival.

He said: "I'm confident we can give anyone a game and if we keep picking up points we'll have a great chance - but I do feel we need to add more quality to the squad.

"We have to get over the hurdle of games where we have a better chance of winning. That's why we need some more creative quality, which the top teams have and which will help us open up teams in games where we're expected to pick up points.

"I'm optimistic of bringing people in, but I will keep the business quiet and there's a lot of speculation."