Arsenal's Premier League title hopes suffered a crushing blow when they conceded a last-minute goal to lose 2-1 at Bolton Wanderers on Sunday.

Bolton substitute Tamir Cohen headed the winner, leaving Arsenal nine points behind leaders Manchester United with four games left and almost certainly ending their bid to claim a first trophy since 2005.

Arsenal went into the match on an unbeaten 16-game run but a succession of draws had allowed United, who beat Everton 1-0 on Saturday, to open a gap at the top of the table.

"It is difficult to swallow the way we lost," Arsenal manager Arsene Wenger told Sky Sports.

"We had chances to win it but didn't take it and in the end we were caught in the way we feared today, from a corner. The week we have just had summed up our season -- lots of quality in our game on Sunday, Wednesday and today but not enough rewards for our effort. We could have had nine points but we got two."

United lead the way with 73 points, champions Chelsea are second on 67 and Arsenal, who have won only one of their last seven league games, have 64.

Manchester City, who visit Blackburn Rovers on Monday, are fourth on 56 with Tottenham Hotspur on 55.

Bolton were unrecognisable from the team thrashed 5-0 by Stoke City in the FA Cup semi-finals a week ago.

Their players used the match programme to apologise to their fans for their performance at Wembley and they certainly set about the match as if they had a point to prove.

Lee Chung-yong missed two good chances before they took a deserved lead in the 38th minute. Gary Cahill's header from a corner was blocked on the line by Samir Nasri but Daniel Sturridge nodded in the rebound for his seventh goal in nine games since arriving on loan from Chelsea in January.

Bolton were awarded a soft penalty 30 seconds into the second half when Sturridge went down under little pressure from Johan Djourou but Kevin Davies shot weakly at Wojciech Szczesny.

Three minutes later Arsenal were level when Robin van Persie played a great one-two with Cesc Fabregas, who hit the post late in the first half, before scoring from the edge of the box.

A great save by Jussi Jaaskelainen denied Nasri in the 70th minute but though Arsenal, who were seeking a ninth successive victory over Bolton, dominated possession they struggled to test the keeper further.

Instead it was the home side who struck when Cohen, on the pitch for four minutes, powerfully headed home a corner.

He celebrated by tearing off his shirt to reveal a t-shirt bearing a picture of his father Avi, the former Liverpool player who died after a motorbike accident in Israel in December -- and collected a mandatory booking for his actions.

"After last week, we wanted to show the fans we had the passion to prove to them that was just one bad day," Sturridge told Sky Sports.

"I have done my team Chelsea a favour today but I came out here to work for Bolton and their fans."

Bolton manager Owen Coyle said: "I think everyone knows how bad we felt after the FA Cup semi-final and it was important we showed our character today -- and we did that.

"We dealt Arsenal's title hopes a big blow but more important for us was our performance. I think we showed the real Bolton Wanderers today and went a long way to putting the smile back on our fans' faces."

Arsenal host Manchester United in their next match on Sunday.

Fernando Torres finally scored his first goal for Chelsea on Saturday as the champions beat West Ham United 3-0 to remain six points behind Manchester United after the leaders had beaten Everton 1-0.

The Spaniard came off the bench to score Chelsea's second six minutes from time -- his first goal in his 14th appearance for the west London club he joined from Liverpool for 50 million pounds ($82.81 million) in January.

"I have had 14 games waiting for a goal, which was not the beginning I was expecting when I signed for a massive team like this," Torres told the BBC. "There will be less pressure on me now. Now we can try and finish the season as we all want."

Sixth-placed Liverpool thrashed Birmingham City 5-0 at Anfield, helped by a Maxi Rodriguez hat-trick.

Everton were unbeaten in seven league games going into the match at Old Trafford but their record at the ground is dire, with their last win coming in 1992.

They were unable to end that drought on Saturday, although, well-organised and hard-working in defence, they kept United at arm's length for much of a sweltering afternoon.

United, beaten in the FA Cup semi-finals by Manchester City last weekend and held 0-0 at Newcastle United on Tuesday, cranked up the pressure in the last 15 minutes.

They got their reward when Hernandez rose well to meet an Antonio Valencia cross and power in his point-blank header.

United have now won 16 and drawn one of their 17 home league games. Victories in their next two league matches would secure the title with two games to spare but they are unlikely to be easy -- away to Arsenal and at home to Chelsea.

"Today's game was tricky. Everton are very resilient and some of their defending was fantastic," United manager Alex Ferguson told the club's website (www.manutd.com).

"We had shots blocked near the line, some misses and the goalkeeper made two or three great saves. You say to yourself: `It's going to be another late one here.' You can just smell the history of the club and so it was to be."

The day's scorching heat was replaced by a thunderstorm for the evening game at Stamford Bridge and for long periods Chelsea struggled to cope with the awkward conditions and some spirited play by their lowly London rivals.

Chelsea grabbed the first goal at the end of the first half when Frank Lampard banged in a low cross from Ashley Cole.

Centre back David Luiz rattled the bar with a 25-metre piledriver before Torres came off the bench in the 76th minute and, eight minutes later, swept in his first goal.

The Spaniard, who was mobbed by every one of his team mates, then set up Florent Malouda for the third.

Chelsea manager Carlo Ancelotti said it had been a perfect day. "Everyone expected Fernando to score and finally he scored and for him from today will be a new life," he told ESPN.

Torres dedicated his historic strike to the club's supporters.

"From my first day here I felt the support of the people everywhere I went. Even when we played away; All of them were shouting my name and they were even more excited with my first goal than me. I know they're happy now and, thanks to them, I feel very good as well," The Sun quoted Torres, as saying.

"It's very important to have a good relationship with the people. I hope this goal will be the first of many for them," he added.