Daniel Ricciardo admitted that he had just wanted to cry when the MGU-K unit on his Red Bull started to fail early in the Monaco Grand Prix.
Ricciardo had started the race from pole position after dominating Saturday's qualifying session. He had been clear favourite to win his first Monaco event this weekend.
"The start went well, and I was like 'I've pretty much done the hard part, let's just finish this race,'" he recalled.
"And then I think lap 18 or something, I exited one corner and I just felt like pretty much no power compared to what I was used to.
"I wanted to close my eyes and start crying, because I thought that was it. That race was over."
It was a potentially devastating blow for the Australian, who has never got over failing to win the race in 2016.
Victory had slipped through his fingers because of a pit stop miscue while he was leading the race and looking certain to win.
"When the lap I got the problem today, all I was thinking of was 'What the hell do I need to do to win this race?'
"I've done everything this weekend, I did everything in '16 - that's why I just wanted to close my eyes and go and hide in a corner."
"Then when [race engineer] Simon said it's not going to get better, but it is what it is - I was like, alright, well maybe I can pull off a great victory and maybe the satisfaction will be even higher!
"We changed a lot of things, they didn't fix the problem but we had to just survive with that problem all race. That wasn't fun, that sucked.
"I'm exhausted," he admitted. "I look forward to a drink very soon."
The problem with the kinetic energy recovery system had left him around 25 per cent down on power for the majority of the race, with Ferrari's Sebastian Vettel right on his tail.
"I only used six gears for the rest of the race," he explained. "We've got eight on a Formula 1 so that's kind of an example of how down on power we were. We don't use all eight here, it is a short track, but still we were down a lot.
"I was just managing the tyres a lot, so at the end I was pushing a bit more, but it was still costing me I don't know, I would say a good second a lap. A lot.
"Also because the rear brakes get hot because of the [MGU-]K that failed. So the rear brakes got really hot, we had to go seven per cent forwards with the brakes. For example maybe we change it one or two per cent during a whole race, so to go seven per cent is a lot.
"We got home just using six gears, so thanks to the team we got it back. I'm stoked!" he beamed. "A lot of things to manage, but we did it. And who cares? We did it!
"They made it hard for me, but we got it done."