Oscar Piastri remains confident in his Formula One world championship chances after Lando Norris and Max Verstappen slashed his lead at the United States Grand Prix.

Piastri endured a difficult weekend in Austin, colliding with McLaren team-mate Norris in Saturday's sprint as both were dumped out before managing only fifth in the race as Verstappen eased to victory.

Norris' second-place finish meant he cut the gap to Piastri to just 14 points, while Verstappen's 33 points across the weekend saw him reduce his deficit to the leader by 23 points to 40.

Momentum is not with the Australian as he finished behind both Norris and Verstappen for the fourth race in a row. Neither McLaren driver has won since Zandvoort five races ago - after which Verstappen was 104 points off the lead.

Piastri, a former F2 and F3 champion, acknowledges the need to turn around his form but remains happy with his position with five rounds remaining and 141 points to fight for.

"I'd still rather be where I am than the other two," Piastri said.

"Definitely Max and Red Bull have found a lot of pace since the summer break as well. We saw flashes of it at the start of the year, but it's been consistent since then.

"I've been in fights that were as close or at this point even closer than what they are now. So I've got the evidence for myself that things can still turn out well and I still fully believe that I can win the championship.

"This weekend has obviously been tough and the gap has come down a little bit in the last few weekends."

Pole-sitter Verstappen completed a perfect weekend at the Circuit of the Americas, having also won Saturday's sprint from pole, by easing to a lights-to-flag win by almost eight seconds from Norris.

Norris' hopes of victory were undone by losing out to Charles Leclerc at the start and he had to overcome a race-long duel with the Ferrari driver to clinch second in the closing stages.

What has appeared a two-way title fight for the entire season is now a three-way battle, but Piastri remains relaxed about the threat of Verstappen.

"You know, there's still a long way to go in the championship," he added. "It is still, for Max anyway, he's obviously chased it down pretty quick, but it's not exactly a small gap with five rounds to go.

"Ultimately, if we can find our way again, find our pace, certainly for me find our pace again, then I don't have any major concerns."

Verstappen wrote off his title chances prior to the summer break and admits he would not have believed it if he had been told after Zandvoort that he would be only 40 points behind with four races remaining.

"I would have thought he was an idiot!" he said. "We found a good way with the car, simple as that.

"We need to be perfect until the end to have a chance."

Oscar Piastri bullish over F1 title chances despite seeing championship lead cut