Singapore GP: Rivals fear Sebastian Vettel is out of reach

Vettel was one second faster than Nico Rosberg in the fastest non-Red Bull during the quicker second session.

Asked if he thought the gap to Red Bull would close, fourth-fastest Lewis Hamilton replied: "I think it will reduce slightly perhaps, but I might be wrong.

"As always every Friday night we have to try to pull a miracle out of nowhere."

Kimi Raikkonen believes his Lotus is more competitive than his eighth place on Friday suggests, but that Red Bull is out of reach.

"There was some traffic on the first lap so I am not worried by it," he said of his own position.

"[Red Bull] were so much faster than anybody else.

"I am sure we can do much better, but I don't think we can match Red Bull because there is no chance."

Vettel remained adamant that Mercedes in particular would be a pole threat.

"Maybe they didn't have the cleanest lap but we expect Mercedes to be very strong, especially in qualifying form, tomorrow," he said.

"I think [the gap] is a bit of a surprise. I got a good lap to be honest, it was a bit surprise how much I could improve from the medium to the super-soft, so it is not completely representative."

Team-mate Mark Webber was 0.6s slower than Vettel but 0.4s clear of the rest.

"We can't focus on the other guys," he said.

"If they are in trouble in our mirrors on Sunday night then it is a bonus, but if they are not it won't be a surprise."