Toto Wolff insists his Mercedes team could still miss out on Formula One glory this season despite leading both championships.

Lewis Hamilton heads team-mate Nico Rosberg in the drivers’ championship by 21 points with Ferrari’s Sebastian Vettel, a winner at the Hungarian Grand Prix in July, 42 points adrift of the Briton.

Mercedes, who have won eight of the opening 10 races this season, are also 147 points clear of Ferrari in the race for the constructors’ title.

But Wolff, mindful of Hamilton and Rosberg finishing sixth and eighth last time out in Hungary, and their first-lap collision at Spa-Francorchamps 12 months ago, insists neither title race is a foregone conclusion.

“With 10 races down and nine to go, we enter the second half of the season with a stronger points total than at this stage last year, and yet our margin to the competition is actually smaller,” said Wolff ahead of this week’s Belgian GP.

“There is never a moment you can take your foot off the gas and Hungary proved once again that any slip is an opportunity our rivals will grab with both hands.”

The Mercedes motorsport boss added: “We have all enjoyed a chance to recharge over the summer but we have also kept our minds focused on what lies ahead.”