Fernando Alonso led from pole position to the checkered flag for Ferrari in tonight's Singapore Grand Prix with a flawless drive, fending off a persistent challenge from Red Bull's Sebastian Vettel.

"It was very difficult, we knew that this is the toughest race of the season," Alonso said. "It was tough to drive. This win means a lot in the fight for the championship."

Championship leader Mark Webber took a crucial third place with the help of an alternate pit strategy, pitting early for hard tires during a safety car period, and leapfrogging McLaren drivers Lewis Hamilton and Jenson Button when they stopped for their tires.

Hamilton made an attempt to take back third from Webber just before the midway point of the race, but his desperate lunge backfired as the two made contact, and Hamilton had to retire with a broken suspension.

The result extends Webber's championship lead but moves Alonso into second place in the points, just nine points adrift of the Australian. Hamilton is now 20 points away, his title hopes having taken a major blow.

All top 5 contenders still within contention after Singapore Grand Prix: 1. Mark Webber - 202 2.Fernando Alonso - 191 3.Lewis Hamilton - 182 4.Sebastian Vettel - 181 5. Jenson Button - 177

Button finished fourth, ahead of Nico Rosberg and Rubens Barrichello.