Lewis Hamilton has said he is under no illusion that his championship lead could evaporate, calling on his Mercedes team to "pull their socks up".

Hamilton will head to Sochi for Sunday's Russian Grand Prix with a 96-point cushion over Charles Leclerc and Max Verstappen, while Sebastian Vettel – who triumphed in Singapore on Sunday – is a further six back.

It seems improbable that Hamilton will not close out the Formula One World Championship with just six races remaining and 156 points left to play for.

"We will go to Russia and try to rev ourselves up and do a better job – but these next few races are going to be tough."

Hamilton's Mercedes team won the opening eight rounds this season, with the Briton triumphing six times.

But since his commanding win at the French Grand Prix in June, Hamilton has won just two of the ensuing seven rounds. His team-mate Valtteri Bottas has not tasted victory since April.

"I am a realist so I see the situation we are in," he said. "Clearly, Ferrari's car works really well everywhere now so it is going to be very hard to beat them.

"Of course, the battle has got tighter and we welcome that. But at the same time we have just got to be doing a better job.

"We did such a great job at the beginning of the year. We have just got to re-huddle and work together."