Lewis Hamilton unsure F1 title momentum will swing back his way

The reigning world champion surrendered the championship lead in Singapore as Rosberg won his third successive race to move eight points clear.

It comes after Rosberg won the first four races and led by 43 points only for Hamilton to score six wins in seven and take a 19-point lead going into the summer break.

While Hamilton has already responded to Rosberg enjoying a run of success earlier in the season, the reigning world champion is not certain the same thing will happen again before the end of the year.

"We're both fiercely competitive," he said. "Some weekends he does great, some weekends I do great.

"I have no idea if the momentum will swing back to me or when it might.

"But we still have six races left, so I just have to keep giving it my all and hope for the best.

"It's going to take some good results to get back in front and stay there - but I've had plenty of those in the past, so there's no reason to think they won't come back to me again."

Rosberg played down his rise in form and highlighted the challenge posed to Mercedes by Red Bull and Ferrari.

"I've had a good run lately and I'm enjoying the moment," he said.

"But as far as the next race goes, or the next one after that and so on... it's anyone's game.

"Red Bull and Ferrari are both pushing us really hard, so there will be some tough weekends ahead."

Mercedes chief Toto Wolff said the battle between Hamilton and Rosberg this season is getting the best out of both drivers.

"This year more than ever, we've seen that they are pushing each other to new heights," said Wolff.

"We're entering a gruelling phase of this record 21-race season, where the physical and mental challenge of a championship reaches its absolute peak.

"We're in good shape - but we must remain on our toes to get the ball over the line."