Sebastian Vettel reckons his Red Bull had the pace to win the European Grand Prix at Valencia had his RB8 not lost drive on lap 35 of the race.
The world champion dominated the race from pole position and retained his lead through a chaotic safety car period.
He was re-establishing his advantage when he pulled off the racing line, allowing eventual race-winner Fernando Alonso through into the lead.
"The engine stalled, the engine switched off and there's nothing that we could have done - at the moment we don't know what the problem was - maybe it was similar to the issue Mark [Webber] had on Friday," said afterwards.
"The safety car was obviously not ideal for us and it might be that the retirement in some regards is also down to the safety car so it's a shame.
"It's s**t but you can't change it now," he added. "I think up to that point it was clear that we were very strong and I felt happy in the car. We had the pace and we were very, very quick today. I was surprised, it felt really good. Also after the safety car the initial restart was okay so..."
Vettel told Sky that he was philosophical about his retirement and said that he drew comfort from the improved competitiveness of the upgraded RB8 over the weekend.
"It's okay," he said. "There is not much we could have done better today. It's just reliability. We all work on the limit and so does the car so, surely it's a shame, but I think up to that point we did everything right. Perfect pitstops, perfect start, perfect race. I think everyone has seen what would have happened.
"Would, could, should; I'm standing here and they are still racing so no chance to win today, but a good step this weekend and hopefully we can carry that momentum into the next grand prix."