Frustation for Hamilton in Singapore
Fernando Alonso made it three wins in five races on another day of bitter frustration for Lewis Hamilton.
Alonso clinched victory in the Singapore Grand Prix by just 0.2 seconds from Red Bull's Sebastian Vettel to move within 11 points of title frontrunner Mark Webber who finished third.
But for the second successive race Hamilton's day culminated in retirement after a collision with Webber on lap 36 as he tried to claim a podium spot.
The first half of the 61-lap race was relatively routine, save for an early safety car at the start of lap three as Vitantonio Liuzzi broke the left-rear suspension of his Force India after pranging a wall.
It prompted Red Bull and Webber to gamble given he had started from fifth on the grid, and had failed to gain any ground once the night race began, making an early stop for tyres.
In fact, the first five away from the line were the first five over it again at the end of the first lap, setting the scene for very few moments of drama until midway through.
It was Kamui Kobayashi who sparked the race to life, initially with the Japanese bundling Michael Schumacher into a wall, a move that appeared a touch over-aggressive.
Within minutes, and without any pressure, Kobayashi then ploughed his Sauber into Anderson Bridge, and unable to take any avoiding action, the Hispania of Bruno Senna ran into the 24-year-old.
That brought the safety car into play for a second time on lap 32, bunching up the entire field, before exiting after four laps.
Webber's early move for tyres had allowed him to move up to third by that point - after he had initially dropped to 11th - ahead of Hamilton and Button, with Alonso and Vettel in a league of their own out in front.
Neither Hamilton nor Button had been able to open up a sufficient enough gap to allow them to make a stop and stay ahead of Webber.
The safety car, however, ultimately bunched up the field, staying on track for four laps as the marshals winched away the Sauber and Hispania.
At the restart Webber and Hamilton found themselves in amongst two backmarkers in the Virgin duo of Timo Glock and Lucas di Grassi.
Glock paid them due respect, easing to one side to allow them both through, but Di Grassi was not so accommodating and held up Webber.
Coming out of turn five and heading up Raffles Boulevard, Hamilton made his move on Webber and had his nose in front as they approached turn seven.
Webber, though, had the inside line, and as they turned in at the same time the duo collided, with Hamilton coming off worse.
Within seconds he was pulling onto the run-off area at turn eight, his fury obvious as he threw his steering wheel out of the car.
Arguably collecting his thoughts, Hamilton did not move for maybe a minute before finally emerging, snapping his drinks line as he did so, one he had complained shortly beforehand had stopped working.
The stewards immediately called an investigation, followed a few minutes later by a second when Schumacher ran into the Sauber of German compatriot Nick Heidfeld, forcing him into retirement.
As for Schumacher, with a damaged front wing, he limped back to the pits with sparks flying as the nose dragged along the floor.
As both were racing incidents, no action was taken, leaving Webber in particular to claim a crucial third and retain his championship lead, with a resurgent Alonso now his nearest pursuer.
Hamilton has dropped to 20 points adrift, with Vettel 21 as the 23-year-old German was forced to settle for a close-run second.
Button could do nothing about Webber in the closing stages and had to settle for fourth, 1.2secs behind, and dropping to fifth in the standings and 25 points behind the Australian.
Behind the leading quartet, Nico Rosberg was fifth in his Mercedes, followed by the Williams of Rubens Barrichello, with Robert Kubica seventh after a late charge in his Renault.
Force India's Adrian Sutil was eighth, Williams' Nico Hulkenberg ninth, with Felipe Massa in his Ferrari claiming the final point after starting at the back of the grid.
There was still time for a moment of drama on the penultimate lap when Heikki Kovalainen's Lotus caught fire, the Finn stopping on the home straight before grabbing an extinguisher and dousing the flames.
Explaining his incident with Webber, Hamilton said: "I saw Mark made a mistake and got caught by a back marker so I knew I could slipstream him into turn seven and I thought I was enough past him.
"I couldn't see him and turned in and left enough room and the next thing I know I got hit. I don't know what happened. I'll have to watch it on tv and see what really happened.
"Twenty points is massive, and with four races to go that is a big gap. I have to get my head down and hope for something."
Webber said: "It was difficult to get away clean after the second restart and Lewis had a run on me.
"Unfortunately we made contact, which was similar to what happened with Lewis with Felipe in Monza.
"After that I had a decent vibration in the front end of the car and I wondered whether I would get to the finish.
"But I've got third, which I would have settled for at the start of the day, and I'm still in the lead of the world championship."
It is Alonso, though, who is the one to watch and he said: "It was a very difficult race.
"Singapore is physically the toughest race of the season, with no room to breathe with 24 corners.
"So this win means a lot to keep fighting in the championship and with four races to go it seems we can be competitive for those."
Vettel gave his all to try and clinch victory, but had to give credit to Alonso.
"I tried to push him as hard I could into a mistake but he didn't make a major one, and it's also so difficult to overtake him," Vettel said.
"We've come away with some good points. In the end it's good for the team, which helps us in the constructors', and in the drivers' it is still open."
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