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Two-time defending Formula One champion Sebastian Vettel benefited from Lewis Hamilton's gearbox failure early in the race and then held off Jenson Button after two restarts to win the Singapore Grand Prix for the second year in a row on Sunday.

Vettel started third but quickly advanced his position to second on the opening lap. The Red Bull driver then took over the lead when Hamilton suffered his reliability issue on lap 23 and dropped out of the race.

Originally scheduled for 61 laps around Singapore's Marina Bay Street Circuit, the race concluded in a two-hour time limit due to the safety car being deployed twice for separate accidents. The first deployment came on lap 33 when Narain Karthikeyan hit the turn 18 barrier and had the right-front wheel come off of his HRT car. Just after the restart on lap 39, Mercedes driver Michael Schumacher slammed into the back of Jean-Eric Vergne's Toro Rosso, forcing the second caution period. The race concluded after the 59th lap.

Vettel easily pulled away from Button on the last restart and then beat the McLaren driver at the finish by 8.9 seconds for his second win of the season and the 23rd of his already illustrious F1 career. Vettel's first victory this year came in the April 22 Bahrain Grand Prix.

"We benefited a little bit from Lewis' failure, which I could see a couple of laps before that he lost oil," Vettel said. "After that, we had a very strong pace. We had a good start, which got us into second and into the hunt. I'm very happy and proud, because this is such a tough race to win."

Both Vettel and Button rebounded from disappointing finishes two weeks ago in the Italian Grand Prix. Vettel sustained an alternator problem in the closing laps, while Button endured a fuel system issue just past the halfway point.

"It's nice to be back on the podium," Button said. "If we can solve our reliability issues, we'll definitely have a chance of fighting for the win in all six remaining races."

With the win, Vettel moved up to second in the world championship standings. He is now 29 points behind Ferrari's Fernando Alonso, who finished third.

"There's a lot of races left, and it's a bit difficult to predict what's going to happen," Vettel said. "We have to make sure that we finish the races first of all. I think the pace is there. Even if we are not quick enough to win, then it's good enough to collect a lot of points."

Alonso entered this race with a 37-point lead over Hamilton.

"I think it was a very positive weekend," Alonso said. "Of the four (title) contenders, we lost points with one (Vettel), but we increased our advantage with the other three."

Paul di Resta's fourth-place run marked the career-best finish for the Force India driver. Nico Rosberg from Mercedes placed fifth, followed by the Lotus duo of Kimi Raikkonen and Romain Grosjean.

Felipe Massa from Ferrari, Toro Rosso's Daniel Ricciardo and Vettel's teammate, Mark Webber, completed the top-10.

After finishing last, Hamilton fell to fourth in the standings. He is now 52 points behind Alonso. Hamilton won the Italian GP and then continued his momentum by winning Saturday's qualifying for the Singapore GP.

"It's heart-breaking not to have finished the race today," he said. "We definitely had the pace to win this weekend."

After reviewing the incident between Schumacher and Vergne, the race stewards penalized Schumacher for causing the collision. The seven-time F1 champion received a 10-spot grid penalty for the next round -- the Oct. 7 Japanese Grand Prix.

"It was obviously a very unfortunate ending to my race when I ran into the car of Vergne, who accepted my apology straight afterwards," Schumacher said. "I am not totally sure why it happened like this. I was braking, but the deceleration was not as strong as it usually would be."