Mark Webber believes a timing mistake prevented him from qualifying better for the Malaysian Grand Prix.
The Red Bull driver qualified only fifth, running the whole of Q3 on one set of intermediates, while Red Bull teammate Sebastian Vettel took pole after a stop to change to a second set of Pirelli inters.
Webber had been well-positioned to be the last driver to start a flying lap, often an advantage in mixed conditions, but slowed too much letting Lewis Hamilton by.
"I think we got the best from the car when we were pushing," said the Australian. "But we didn't push when the track was at its quickest. To do the absolute maximum lap time probably another set of inters was the right thing to do, but it wasn't completely clear.
"I was saving my inters for the last run, but the information I had on when the session was going to finish was a little bit different to what I thought. I got the flag and I wasn't expecting the flag. I thought we had more time."
Webber nevertheless thinks that taking pole on his older intermediates would have been difficult even if he had managed another lap.
"If you look at a scrubbed tire against a new tire toe-to-toe in the same conditions I was probably going to struggle against Seb, but we could certainly have done a stronger lap time," he added.
Although Webber believes Red Bull has made progress on looking after the tires over a race run, he admits the competitive order is still unknown.
"We could be very strong, we're just not sure," he said. "People have different ideas on what they might need tomorrow. Any long runs around this place are difficult on the tires.
"It's certainly going to be a very interesting grand prix, extremely open."