Valtteri Bottas says he had to back off repeatedly to preserve his engine during the Australian Grand Prix and suspects Mercedes left too little margin with its cooling package.

Bottas climbed from 15th on the grid to finish eighth but revealed he had to drop back from other cars to keep his power unit cool.

“We expected it was going to be difficult,” said Bottas. “And we knew you need a big pace difference, delta, to overtake, if the other guy doesn’t do any mistake. Especially if there’s a train of cars like I had in the whole second stint.”

“And there was not much things happening that was really helping me. I think the Virtual Safety Car maybe I gained a little bit, stopping under that.

“Other than that it was a pretty frustrating race in the end because we do have a good car but there was nothing I could do. I was trying to take all the opportunities, got some overtakes.

“On top of that what was really limiting us today was overheating. I think there was something wrong with the calculation for the cooling we estimated for today so I couldn’t really be close to other cars so I couldn’t put pressure on other cars for long, I could only be, like, two laps and then I had to back off, try again. So it was not quite ideal.”

Although Bottas didn’t have to switch engine modes to reduce stress on the engine, he said the need to back off for the engine restricted his pace more than tyre degradation. “I never could push as many laps in a row that I had issues with overheating of the tyres.”

Lewis Hamilton was told on several occasions at the end of the race to back off to reduce engine temperatures while he was chasing Sebastian Vettel.

Go ad-free for just £1 per month >> Find out more and sign up

2018 F1 season