Toto Wolff says the threat posed by Ferrari will give Mercedes some tough decisions to make in the second half of the championship.

Lewis Hamilton currently sits top on 202 points, with team-mate Nico Rosberg second, 21 points adrift. Sebastian Vettel is a further 21 points back but after the four-time world champion took his second victory of the season in Hungary, Wolff says Mercedes is unable to turn a significant amount of its attention to next season’s car while Vettel poses a threat.

"We'll have to be good at balancing the development of this machine with the need to work already in the project in 2016,” Wolff told La Gazzetta dello Sport. “For now we are still 100% focused on the present, because Vettel is just 42 points from Hamilton."

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Asked if he sees Vettel as having a realistic chance of winning the championship, Wolff replied: “Sure.

“Seb has a gap of 42 points from Lewis and 21 from Nico, when there are still 225 at stake. As Budapest demonstrated, just one crooked race and everything is reopened. The possibility of losing this title is low but you have to be aware what can happen and therefore it is good to keep your feet planted on the ground.”