Thierry Henry scored twice in Arsenal's 2-0 win at Villa Park that saw Arsene Wenger's men take a two-point advantage over Manchester United, who crashed to the surprise defeat of the season at struggling Wolves on Saturday.

Both of Henry's goals angered Villa. His first, in the 29th minute, came after referee Mark Halsey allowed him to take a quick free-kick as the Villa defensive wall was still lining up.

And Villa were unhappy with the penalty Halsey awarded in the 53rd minute when Olof Mellberg halted Nigeria striker Nwankwo Kanu, in his last match before departing to the African Nations Cup, in the box.

Henry beat Villa's German keeper Thomas Sorensen from the spot.

Villa manager David O'Leary branded the free-kick a "joke decision" and added: "The two decisions have cost us. It just wasn't a penalty."

Reflecting on Arsenal's first goal, O'Leary said: "In my opinion it was a joke decision. He (Halsey) was standing on the ball... We did what the referee told us. He's told my players to go back and wait for the whistle."

The referee, however, said he had not spoken to Villa players at the crucial moment.

"After the free-kick was given to Arsenal I said to Thierry Henry did he want a quick free-kick or (the Villa players moved back) 10 yards. He said he wanted to take a quick free-kick. I made a signal and moved back.

"In law, I'm under no obligation to inform the Aston Villa players or blow my whistle at a free-kick."

Even Wenger admitted there was a problem with the free-kick regulations. "At the moment the rules are not clear," the Frenchman said.

Arsenal's win left them two points clear of their title rivals and extended their unbeaten league record to 24 games.

Third-placed Chelsea's title challenge suffered a setback Sunday when an outstanding display from Birmingham keeper Maik Taylor kept their strikers at bay and the match finished goalless.

So instead of fully capitalising on Manchester United's defeat, Chelsea moved to six points behind the Gunners and four shy of second-placed United.