Though he has yet to out-qualify his teammate this season, Stoffel Vandoorne's form at Silverstone and again at Hockenheim, indicated that the Belgian was suffering a serious performance issue.

Having described last Friday in Germany as his worst Friday ever since he began racing, it was followed by his worst Saturday, the youngster propping up the timesheets in almost every single practice session, qualifying and finishing the race 13th.

With the support of his teammate, Fernando Alonso, who called on the team to investigate the cause of the issue, McLaren has opted to revert to the Belgian's old chassis this weekend as its investigations continue.

"We have swapped the chassis," Vandoorne told reporters. "It's not a brand new one, it's one we've used before but that's not a problem at all.

"I was pushing the team for it," he added. "Obviously what we did over the past couple of races, we started to change a lot of parts and there came a point where we nearly did everything we could and that was one of the last pieces remaining. It's not easy for the team to do that, especially when it's a back-to-back race. But they've managed it."

However, Vandoorne concedes that the problem may not be the chassis, and that he will have a better understanding following Friday's practice sessions.

"There's not specific area we can say 'okay, that's what caused it'," he admits. "I think tomorrow we have a couple of tests in place across the cars to further understand. Hopefully we can spot nothing because that means the two cars are going to be good.

"They saw already from Silverstone that there was something going on but it was hard to tell that it is a chassis-related issue.

"At the moment we haven't driven the car yet, so we don't know, but we've kind of done everything now to remove the doubt.

"You start thinking about everything," he admitted, revealing that the continued issues had led to self-doubt, "but at some point there were sessions where I couldn't even match one corner to Fernando anymore. Then you know, if you can't even match one corner, you know there is a problem on the car.

"Hopefully we can start the weekend here from zero without any problems and just actually have a normal weekend again. That would be a nice feeling."

Check out our Thursday gallery from the Hungaroring, here.