Mercedes team principal Toto Wolff has revealed that Lewis Hamilton was perilously close to suffering an engine failure as he rounded out victory at the Brazilian Grand Prix. Hamilton benefitted from Max Verstappen's crash with Esteban Ocon to take his first victory after winning a title mid-season.
Hamilton qualified on pole, but the Silver Arrows were largely helpless as Verstappen stormed through the field and took to a second stint on quicker tyres than the Brit – allowing him to take the lead near the halfway point.
Although things came back Mercedes' way when the Red Bull spun, Hamilton revealed that he begun to feel something troubling brewing underneath him as the win neared.
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, so I just stay focused on trying to do less full throttle lifting and going as easy as I can on the engine."
And Wolff revealed just how critical the situation was for the 2018 champion, whose victory helped Mercedes wrap up their fifth consecutive constructors' title.
"We have the engine guys here at the track and then we have them back at base, and what I could hear - because I have about 10 radio channels open - on one of the 10 channels, the meeting channel, was 'Lewis Hamilton power unit failure imminent, it's going to fail within the next lap'.
"I put the volume up and I was like 'Excuse me, what?' And they said 'Yeah we've got a massive problem on the power unit, it's going to fail next lap'. It didn't fail next lap and I said 'When you guys have a minute, tell me what's happening". So I let them work.
"And they said 'Well our exhaust is just about to fail and we're overshooting all the temperature limits'.
"So I said 'What's the fix?' And they started to fix it by turning the whole thing down. The temperatures went down to below 1000C, to 980C, but it's still too high, and then he recovered another lap and that was truly horrible."