Di Resta's biggest problem? Undersized boots!

Paul di Resta knew his unexpected F1 comeback would likely pose a physical challenge, he just didn't expect it to involve his feet!

The Williams substitute, who filled in for an unwell Felipe Massa at the Hungarian GP, acquitted himself well following Saturday's last minute call.

Di Resta felt he could handle the procedures but admitted the race on the twisty Hungaroring layout, and behind the wheel of the faster new-spec car, could throw a physical challenge his way.

If he indeed felt some pain in the upper part of his body at the end of the day, the biggest sting was felt in his feet! 

"It's been quite hard," said di Resta after the race.

"I can certainly feel it in my shoulders, but the biggest thing is the feet. The shoes are a bit too small. My feet were killing me."

• Massa withdraws from Budapest test

A leak prevented the Scot from reaching the checkered flag, but the 31-year-old's performance did not go unnoticed, and he is hoping his one-off drive will lead to a more permanent opportunity. 

"There's no secret I want to be in a Formula 1 car, but at the very least I hope I've showed I'm a reliable reserve driver kicking around the paddock.

"I tried to approach it in the most professional way I could and gain a lot [of experience] rather than throw away something that wasn't there [in terms of a potential result]."

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