Ferrari Formula 1 driver Sebastian Vettel says he regrets being so conservative on his first United States Grand Prix Q3 run after losing pole to Valtteri Bottas by 0.012 seconds.
Vettel finished the first Q3 attempts just behind his Mercedes rival, but was confident of doing better on the final run because he had taken things quite easy in the final sector to ensure he had a solid banker lap.
But Vettel's hopes of snatching the top spot were derailed when the track conditions fell away at the end of the session, leaving both him and pole position man Bottas unable to improve on their final laps.
Vettel said such a small margin of difference between second and first was particularly hard to accept because of how he had handled his opening run.
"Obviously it was a very nice session, really fun to drive the car this afternoon, but if you are so close to pole and just on the wrong side of it, then I guess Valtteri had a bit more fun," said Vettel.
"I had a very good first lap and had some margin in the last sector. I was maybe taking it a little bit too conservative making sure I should have finished the lap and set the lap first, and then improve on the second lap.
"Unfortunately I didn't improve, so my plan didn't quite work.
"Overall it was good. I think we will have a strong race tomorrow as the car felt better today than yesterday, which is also what we needed."
Bottas said that the key to his turnaround in form from a difficult practice day on Friday was a big overhaul of his set-up overnight.
"I am really happy about that, it was a nice lap at the beginning of Q3 to get those kind of laps, and on a track like this it is a good feeling," he said.
"Yesterday was tricky, there were many things not quite right with my car, but we managed to find all the reasons and it was good work this morning with finding all the details and good time.
"I knew how to bring it together but to bring it together was a nice feeling for Q3."
Bottas needs to win the race to have any hope of taking the world championship battle with team-mate Lewis Hamilton onto the next GP in Brazil.
He said Mercedes' recent strong race form gave him a level of confidence about his chances.
"We've seen recently normally on Sundays we've been competitive, so it's very good starting from pole here," Bottas added.
"There are some corners that are difficult to follow for the cars behind, and we have the pace."