The Gunners, who began the day three points behind Villa as the two fight it out for a Champions League place at the end of the season, survived a first-half battering to somehow lead 2-0 through Denilson and Abou Diaby.

However, a Gareth Barry penalty paved the way for a comeback and stand-in centre-half Zat Knight smashed home a crucial leveller in added time.

Villa won the penalty after William Gallas went to ground when challenging Gabriel Agbonlahor just inside the area and Wenger indicated referee Mason was influenced by the partisan atmosphere.

"I know how it works here," he said. "At half-time the referee gets stick and then in the second half every little 50-50 decision goes the other way.

"That's what happened. It's not only here.

"I waited at half-time to see what happened and I was not disappointed."

Asked if he was implying a member of the Villa squad or backroom team influenced referee Mason, Wenger said: "I have nothing to explain more than that.

"I still believe that for the penalty the first foul was by Agbonlahor on Gallas and the second foul was by Gallas (on Agbonlahor)."

O'Neill admitted assistant John Robertson asked Mason about a first-half decision - Villa believed Agbonlahor was obstructed moments before Denilson scored - but played the incident down.

"I couldn't give you any response to that. I think the referee must have seen, at half-time, that the decision he gave for Gabby Agbonlahor (before Arsenal scored) was not his best one. Gabby was fouled I think, it was obstruction, and the referee must have been at least three yards away.

"But I didn't tell him on that particular occasion. Arsene Wenger has his own opinion about it and I believe we deserved at least a point today if not all three. Our first-half performance was incredibly exhilarating and a joy to watch.

"John Robertson, I think, spoke to the referee. I think John asked him to explain the decision that Gabby didn't get, that was all. Simple as that.

"He only asked him to explain the decision and the referee chose not to give an answer."

Wenger, meanwhile, also admitted his side's failure to hold on for a win was a real blow.

He said: "We are disappointed because we were close to the win and we conceded the equaliser. Especially at that moment, when Villa had not created a lot in the second half.

"They had chances in the first half but in the second they didn't create any chances.

"I believe the turning point was at 2-1, because we lost composure and there was plenty of room to keep the ball much better but we were a bit nervous just to get over the line.

"In the end it cost us."