The Professor didn't turn to complex calculations or the tactics' table to determine where it all went wrong for Arsenal for a fourth straight season.

Arsene Wenger concluded that his failure to recapture the Premier League title is simply down to being unlucky.

Ditto for European play.

The week when the Arsenal manager's Champions League ambitions were extinguished by Liverpool worsened yesterday when Manchester United rallied for a 2-1 victory that wiped out any lingering hopes for a domestic championship.

And just like at Anfield, his side was done in by a late disputed refereeing decision after dominating the first half.

"I'm very proud of my team and we have to continue producing the kind of football we produce and not always be unlucky," Wenger said. "We played very well at Liverpool and today five days later. With all the things that went against us recently we have to be exceptionally strong to produce a performance like we did here."

Making amends

Arsenal were determined to make amends for February's humiliating 4-0 FA Cup defeat to United, which triggered a slump that saw the club lose a five-point lead atop the league.

Emmanuel Adebayor gave his team hope by giving Arsenal the lead three minutes after the break, nudging the ball over the line with what appeared to be his arm.

But Cristiano Ronaldo equalised on a penalty six minutes later after William Gallas blocked the ball with his hand and Owen Hargreaves curled a free kick into the net in the 72nd, with Jens Lehmann stranded at the far post.

Wenger criticized referee Howard Webb for giving that free kick, after Gilberto was deemed to have fouled Patrice Evra. Wenger struck a similar tune after a disputed late penalty against Liverpool sent Arsenal out of the Champions League on Tuesday.

"I believe defensively we played quite well," Wenger said. "We lost on a penalty you can give it, you can not give it, but we are used to it now. On the free kick he didn't touch him, Gilberto. I believe these two decisions made of course a big difference."

Arsenal emerged as the team to beat early in the season with a scintillating display of offensive-minded soccer before the talented - but small - squad ran out of steam.

Very difficult

"The difference between success and failure this season was very little and in the end we have to accept we won't win the title," Wenger said. "It's very difficult to swallow because we don't think there's a difference in the technical quality between us, Chelsea and Manchester United."

Chelsea trail United by six points, but have a game in hand. Arsenal are now nine points behind the United, after holding a five-point lead in February.

"The last two months, we have been not very lucky and you could see that again," Wenger said. "The confidence has dropped a little bit going through a difficult period in the last two months.

"You can't fault the spirit, which has been exceptional. When you get knock after knock it's difficult to take."

Despite the lack of trophies, Wenger insists his players' silky soccer is beneficial for everyone.

"We feel that we have done a lot for the promotion of the Premier League all over the world," he said. "We want to continue playing that way, as well as playing better. The trophies will come, there is a thin margin between winning and losing.