SEPANG, Malaysia (AP) — French driver Romain Grosjean escaped without injury after clipping a loose drain and flying into the crash barriers in the second practice for the Malaysian Grand Prix on Friday.

His tire shredded on impact, catapulting him at full speed from one side of the track to the other. It ended the session with 20 minutes left and, moments later, race director Charlie Whiting and another official from motorsport governing body FIA inspected the damage.

It was a spectacular incident but without consequence.

Grosjean climbed out of his Haas car unharmed, and was even able to talk about it pretty calmly moments later.

"I didn't see anything. Next thing I knew I was spinning and heading for the wall," he said. "I am fine, that is the most important thing."

But it could have been much more serious, with images showing the drain cover sticking up at an angle before Grosjean clipped it.

"It was on the racing line and I had a big hit and impact on rear right. I was spinning and heading to the wall," Grosjean said, after reviewing footage. "They need to sort things out, it is a shame. Hopefully we find a good setup for tomorrow and the drains stay in place."

Haas team principal Guenther Steiner was furious.

"Things like this in 2017 shouldn't happen on any circuit," he said. "In my opinion this is not acceptable. In a race this would have been a disaster."

Explaining the incident, Whiting said that some welding came loose on a Sepang circuit he claims is "fatigued" as it hosts a race for the last time.

"One drain grate has come up. It just seems that it has broken away," said Whiting, explaining that further checks would be made on other drains during the evening. "We have to get it fixed for tomorrow, of course."

Red Bull team principal Christian Horner was confident the issue would be taken care of.

"The good thing is no one was hurt," Horner said. "I'm pretty confident we won't see a repeat issue."

By the time the second practice was over, Ferrari had done enough to secure a 1-2 as Sebastian Vettel set the fastest time followed by Kimi Raikkonen. Vettel has reason to feel confident of securing a second straight pole position in Saturday's qualifying.

But it was a different story for Mercedes.

Lewis Hamilton and Valtteri Bottas struggled with grip and went off track into the gravel within moments of each other.

Bottas' left wheel locked as he came out of Turn 10. Hamilton, out of Turn 7, skidded sideways and then backward into the dirt.

Hamilton was sixth and Bottas seventh on a poor day for a team that has won three straight drivers' and constructors' championships.

"The car seems to be unbalanced," Mercedes head of motorsport Toto Wolff said. "One of the worst Fridays I can remember."

Renault driver Jolyon Palmer and Toro Rosso's Carlos Sainz Jr. — who is replacing Palmer next year — also went off track. Although there was a heavy downpour before the first practice, the track had largely dried out by the afternoon. Drivers have raced in far worse conditions.

There is a third and final practice on Saturday before qualifying at 5 p.m. local time.

Hamilton has won the last two races and holds a 28-point lead over Vettel, who crashed from pole in Singapore two weeks ago.

Earlier, in first practice, Max Verstappen posted the fastest time, followed by Red Bull teammate Daniel Ricciardo.

Vettel and Hamilton were fifth and sixth respectively.

"We just lacked pace today and we have 12 hours to understand why," Wolff said.

It promises to be a long night in the Mercedes garage.

"We're definitely lacking performance, it seems like Ferrari and Red Bull are very strong," Bottas said. "We have work to do if we want to be on the front row. The key area we are going to need to focus on tonight will be getting the maximum out of the tires over one lap."