McLaren's Jenson Button has predicted that Red Bull will begin the revival of their season with an improved performance this weekend in Singapore.

The sport's dominant team for the previous two seasons have struggled since the beginning of the summer but Button believes that Sebastian Vettel and Mark Webber will provide a threat at Marina Bay.

"There's no reason why we shouldn't be competitive here - we'll obviously be disappointed if we're not," the Brit told Sky Sports News. "The last three races have been good for us. I think that Red Bull haven't been as quick as we expected over the last two races, but they'll be back here competitive again I think. And Ferrari.

"But we've been competitive in qualifying and the races over the last few races and that's really been key to winning the grands prix. Saturday has been more important than we expected this year."

Despite their troubles in recent races, Red Bull continue to lead the constructors' championship.