Brazilian Grand Prix winner Lewis Hamilton’s engine was on the brink of failing during the race, Mercedes Formula 1 boss Toto Wolff has revealed.

Hamilton led away from pole position but lost out to Max Verstappen’s stronger strategy, before the Red Bull driver tangled with Esteban Ocon while lapping the backmarker, ultimately handing the victory to the recently-crowned five-time world champion.

The Briton had reported engine concerns throughout the race but it was not fully revealed until after the race just how close Mercedes came to a terminal failure, which was miraculously averted thanks to some quick work by engineers and adjustments made by Hamilton in the cockpit of his W09.

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"We have the engine guys here in the back and then we have them back at base," Wolff explained.

"I have about 10 channels open, and on one of the ten channels, the meeting channel, I could hear 'Lewis Hamilton, power unit failure imminent. It's going to fail within the next lap.'

"I put the volume up and said, 'Excuse me, what?' And they said, 'Yeah we have a massive problem on the power unit, it's going to fail on the next lap.'

"But it didn't fail the next lap, and I said, 'When you guys have a minute, tell me what's happening.'

"They said 'Well, our exhaust is just about to fail, and we're overshooting all the temperature limits.' I said, 'So what's the fix?'

"And they started to fix it by turning the whole thing down. The temperatures went down to below 1000 to 980 degrees. But it's still too high! That was truly horrible."

Hamilton provided an insight into the frantic situation unfolding inside the cockpit, as he juggled balancing setting changes alongside trying to keep the recovering Verstappen at bay in the closing stages.

"I could feel it," Hamilton said.

"I have been driving this engine since the beginning of the year and I know all about it and how it feels and pretty much every note I know like the back of my hand.

"So when I started to feel it was not operating at its normal harmony - for me I cannot allow any negative thought getting into my mind. I just stay focused on trying to do less full throttle lifting and going as easy as I can on the engine.

"There was a lot of great work that went on in the background with the engineers here, and back in the UK, who were really working on understanding what they've got to turn down and tweak,” he added.

"I was really grateful that the engine finished and for the last 10 laps I was really just shouting in the car 'Come on baby, you can do it. Let's keep it together' and willing on the car.

“My heart rate must have been above 190, those last 10 laps I was at flat-chat trying to hold on to a car, which was already struggling. I just felt so elated and so grateful."