Lewis Hamilton insists Mercedes have a real fight on their hands to stave off the threat from Ferrari.
Hamilton and his Formula One contemporaries return to action in the idyllic setting of the Belgian Grand Prix this weekend following the sport's four-week summer shutdown.
The 30-year-old, who holidayed in America and Barbados during the break, holds a 21-point lead over Mercedes team-mate Nico Rosberg.
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Four-time world champion Sebastian Vettel, winner at the Hungarian Grand Prix last time out before the summer break, is 42 points adrift of the Briton.
But Hamilton believes the Ferrari driver must be considered a serious rival as he bids to become the first British driver to successfully defend his title.
"We are fully aware that other teams are pushing very hard and Ferrari are looking great," said Hamilton, who finished sixth in Hungary following an error-strewn display.
"We don't arrive at any race thinking that we are superior to anyone. We know that we have a fight on our hands and so we're going to work at trying to make sure we work harder than them."
Hamilton conceded his display at the Hungaroring was his worst in seven years, but he somehow managed to extend his lead over Rosberg.
The German could finish only eighth after he was involved in a collision with Red Bull's Daniel Ricciardo in the closing stages of the race.
So, does Hamilton believe such a remarkable result is a clear indicator that a third world title is written in the stars?
"Definitely not. Definitely not," he said. "I think the team effort that goes in - seeing how hard my team is working, seeing the progress we are making - encourages me to believe that this is going to be our year."
Ferrari's Vettel is reinvigorated following his move from Red Bull, winning twice - in Malaysia and in Hungary - and finishing on the podium at five other races.
And the German says he must take advantage of any further Mercedes slip-ups to capture an unlikely fifth championship.
"For sure if we'll have the opportunity like in Hungary to turn things around then we have to go for it," said Vettel, who will be partnered by Kimi Raikkonen once more at Ferrari next season.
"Until now we took the opportunity two times and it worked very well, otherwise we did our best to be right behind, but for sure the advantage of Mercedes is still there and it doesn't just disappear."
New start procedures come into effect for Sunday's race with the emphasis being placed back in the drivers' hands rather than the pit wall. The premise is that it will lead to unpredictable starts and more exciting races.
Vettel added: "We'll have new rules concerning start procedure this week, but I don't think they are going to change much, apart from less radio coaching and fewer adjustments on the clutch. I think in a couple of races we'll know what to do properly."
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