Max Verstappen has confirmed that he collapsed shortly after the end of FP1 yesterday.

The Dutch youngster, who was celebrating his 19th birthday, spoke as rumours swept the paddock.

"After FP1 I think I stepped out of the car a bit too quick," he told Dutch TV. "Things became a bit hazy before my eyes, so I had to sit down for a moment. But FP2 was no problem at all."

Despite the issue, which has affected a number of drivers over the years, especially when the race is held in this part of the year, the Red Bull driver enjoyed a productive day, finishing fifth quickest.

"It's nice to spend my birthday here," said the youngster. "I can enjoy some birthday cake because it's so hot at Sepang I'll lose the kilos anyway.

"Both sessions were pretty good," he added. "I enjoyed the new surface it seemed to have quite a bit more grip. Before, in Malaysia, we seemed to struggle with traction but the changes they have made here appear to have helped. I also think it is a lot more fun to drive.

"Our short runs need to get a bit better," he admitted, "but the long runs are looking strong. The pace on the soft tyre felt decent, I feel like that tyre has potential on a long run and it allowed me to throw the car into the corners like I wanted to."

Check out our Saturday gallery from Sepang, here.