Ferrari's Sebastian Vettel won an incident-­packed Singapore Formula One Grand Prix on Sunday after world champion Lewis Hamilton retired early for the first time this season and a spectator set heart rates fluttering when he strolled on to the track.

Hamilton was running fourth ­approaching the halfway point of the 61-lap race when he started losing engine power, rapidly dropping back through the field before he was told to return to the garage and call it a night.

Starting from pole position, Vettel had no problems, leading all the way to take the checkered flag for the fourth time at the floodlit Marina Bay Street Circuit, despite twice losing the big ­advantage he had built up when the safety car was deployed.

Australia's Daniel Ricciardo finished second for Red Bull, his best result of the year, while Vettel's teammate Kimi Raikkonen crossed the line third.

"It must be one of my best races. It was pretty intense," Vettel said. "Lots of pressure from behind; Daniel had a very good race looking after his tires.

"Second stint I was dictating the pace. From then, I was trying to control the gap. We had a really great weekend."

Nico Rosberg finished fourth for Mercedes to cut Hamilton's championship lead to 41 points with six races remaining. Vettel trails Hamilton by 49 and Raikkonen is 145 adrift with a maximum of 150 available. No other driver has a chance of winning the championship.

"If we have more weekends like this, yes we can catch Mercedes," Vettel said.

"Massive attack. Maybe we can make the impossible possible - we will definitely go for it."

Vettel's win was the German's third this season and the 42nd of his career, enabling the quadruple world champion to overtake the late Ayrton Senna into outright third place for the most lifetime wins, trailing only Michael Schumacher (91) and Alain Prost (51).

A proven master on the slow and twisty Singapore track, Vettel gave his rivals no chance when he stamped his foot on the accelerator and made a flying getaway from the front of the grid.

The 28-year-old opened up a three-second lead over Ricciardo after the opening lap and was never seriously challenged even when the safety car was introduced.

Its first appearance came on the 13th lap when Felipe Massa exited the pits and was hit from the side by Nico Hulkenberg who speared into a wall, wrecking his Force India car and ending his race.

The second came when a spectator briefly walked on to the circuit before climbing back though a hole in the fence.