Lewis Hamilton says the Singapore Grand Prix is the toughest race of the season, ahead of a weekend in which he and Mercedes are expected to struggle against Ferrari.

The reigning Formula One world champion has a 30-point lead over Ferrari’s Sebastian Vettel, but pundits expect that gap to be narrowed given Mercedes traditionally struggle in the season’s only night race – and Ferrari have been strong there in recent years.

Hamilton won an incident-packed race last year, however, and has won in Singapore three times in total. But says the race is a gruelling test of a driver’s skill and stamina.

“Physically and mentally, it is the toughest race of the whole season,” the four-time champion said.