Fernando Alonso cursed a late loss of power on his upgraded Honda power unit which saw him finish without a point at the U.S Grand Prix despite what he called "one of the best" races of his career.
Alonso and team-mate Jenson Button were both running in the top six after the final safety car restart, but the Spaniard soon started losing positions and complaining of a loss of power in his engine. He eventually finished 11th after being passed by Red Bull's Daniel Ricciardo on the final lap.
"I think we would have finished the race in 5th place without the problems, but we ended up nearly last and almost lapped," Alonso said after the race. "It was certainly one of the best races of my life, but with no points to show at the end. We just lost power in the final laps. Yes, the new engine has more performance but we're speaking of just one tenth of a second per lap. It was an electrical problem, because the engine would go and then cut, so I don't think it was a mechanical issue."
Alonso wants the team to investigate the issue thoroughly to ensure it does not happen in the final three races of the season.
"Still we need to investigate it to make sure it doesn't happen again. But I go home with the feeling I drove my best race from the last few years and let's hope we can continue like this until the end of the year.
"I think we deserved to be fifth, the car was going really well, we could make up positions, but a problem with the electrics cost me 30s in 12 laps. It's the kind of issue we seem to keep on having, but hopefully we'll keep on learning and be in a better position next year.
Alonso's verdict on his own race up until the power unit issues was probably influenced by the fact he was nearly eliminated at the first corner after contact with Valtteri Bottas, forcing him into an early stop for a puncture.
"Someone hit me in the first corner, so I spun around and was dead last, half a minute from the next car. We didn't lose hope, we fought and were up to 5th close to the end, with a really strong pace. It looked like we could get a miracle today but then we had the problem, and that was that."
Honda chief Yasuhisa Arai says the manufacturer needs to investigate what went wrong in Alonso's car.
"Fernando's car had been fairly competitive through most of the race, thanks to a combination of his skills and the new Spec 4 engine, which performed to our expectations throughout the weekend," Arai said. "However, we think he temporarily lost power due to a possible injector issue -- which was rectified before the end of the race. We'll need to investigate further to confirm the situation. Needless to say, we are very disappointed that he lost precious points positions because of this issue."