Austin - Lewis Hamilton said Mercedes made life difficult for themselves with a cautious race strategy in Sunday's United States Grand Prix.
The 33-year-old Briton, who finished third, but missed out on clinching his fifth drivers title, told reporters that he was surprised when he was called in for an early pit-stop to take advantage of a Virtual Safety Car intervention on lap 11.
"It was a little bit of a surprise," said the Mercedes man after finishing behind race winner Kimi Raikkonen in a Ferrari and Red Bull's Max Verstappen.
"And once we'd done the stop on 11, I knew I would be doing a two-stop.
"We just made it so hard for ourselves. When we came out, I had to catch Kimi, I caught him, but my tyres were dead.
"Then he did his stop and was catching me with fresh tyres - and then I came out, after the last stop, and had 12 seconds to catch up. It just made it so hard for us even to compete today."
He added that he was also not sure that he started the race on the best tyre.
"I think it already started from Q2, that tyre was the wrong tyre to start on. We knew there was a big difference in start performance on these different tyres, yet we fell for something that we already knew was potentially not the way forward.
"I lost position to Kimi and then I wasn't able to keep up because he had clean air and a better tyre.
"It was definitely a lesson learned, I think, for us. Performance-wise, it wasn't our greatest weekend, but we've had some incredible weekends this year.
"Still, to get a third, I'm still grateful, but naturally, starting first and finishing third is never a good thing."
Despite his disappointment, Hamilton seems assured of wrapping up the title in Mexico next weekend.