Max Verstappen held off a late charge from Lewis Hamilton to take a big win in the United States GP and increase his world championship lead to 12 points with five races to go.
In yet another captivating duel between the title contenders that went all the way to the race's 56th and final lap, Verstappen withstood the pressure of a charging Mercedes on fresher tyres to claim his first win in the USA at a significant time in the season.
"Catching is one thing, passing is another - Verstappen kept his head. That was a very important victory in his career and championship charge," said Sky F1's Martin Brundle of the Dutchman's eighth win of 2021.
- The full result from Sunday's US Grand Prix
- Updated F1 world championship standings
- What races are left? Dates for 2021's final five
Hamilton had brilliantly overtaken his pole-sitting rival into the race's first corner, but Red Bull gained track position by pitting Verstappen first at the opening stops - and then again at the second when he was in the lead.
Mercedes kept Hamilton out longer to ensure significantly fresher tyres for the closing laps and he rejoined from his second stop eight seconds behind Verstappen. He quickly reeled him in but, crucially, Verstappen could just about stay out of DRS range and keep his tyres in check to ensure Hamilton never got close enough to attempt a pass.
"Big for us to beat Mercedes here. I really didn't think he was going to pull that off," said a jubilant yet relieved Red Bull boss Christian Horner, who also saw Sergio Perez finish third in the sister car to ensure they cut the reigning champions' lead in the constructors' chase to 23 points.
A philosophical Hamilton told Sky F1: "We gave it everything we had and they were just quicker than us this weekend."
Charles Leclerc drove a fabulous race to take home fourth for Ferrari, finishing closer to Perez's Red Bull (10s) than fifth-placed Daniel Ricciardo (24s) from constructors' championship rivals McLaren.
With Carlos Sainz seventh, Ferrari moved to within three-and-a-half points of McLaren in the fight between the sport's former titans for third in the teams' standings.
But fifth was still a strong personal result for Ricciardo, three places and eight seconds ahead of team-mate Lando Norris. After overtaking Sainz on the first lap, the Spaniard came back at him later on but a wheel-banging clash between the pair did not change their order.
Valtteri Bottas, who had started ninth after an engine change penalty, overtook Sainz on the final lap for sixth after a tricky race in the second Mercedes.
United States GP: Top 10 finishers
1) Max Verstappen, Red Bull
2) Lewis Hamilton, Mercedes
3) Sergio Perez, Red Bull
4) Charles Leclerc, Ferrari
5) Daniel Ricciardo, McLaren
6) Valtteri Bottas, Mercedes
7) Carlos Sainz, Ferrari
8) Lando Norris, McLaren
9) Yuki Tsunoda, AlphaTauri
10) Sebastian Vettel, Aston Martin
Red Bull win out after high-speed game of chess
With almost a quarter of this gripping 22-race campaign still to come over the next seven weeks, it would be dangerous to read too much into the significance of Verstappen's Austin success but is undoubtedly still acts a timely fillip for Red Bull just when their title challenge just seemed to be losing a little momentum.
Having ended Mercedes' 100 per cent pole record at COTA in the hybrid-turbo engine era on Saturday, Verstappen claimed Red Bull's first win at the Texan venue since their last title triumph in 2013.
Finishing on the top step of the podium had seemed in doubt at several stages of the races - no more so than right at the start when Hamilton sneaked into the lead down the inside into Turn One, despite Verstappen's attempt to close the door.
It was just 10 laps later that Red Bull decided to roll the strategy dice.
"We went very aggressive," acknowledged Verstappen as he was called into the pits.
With Mercedes immediately deciding to run longer with Hamilton to give them the tyre edge later in the race, Red Bull restricted their rivals' options by soon pulling Perez in too - as also advised by Verstappen from the cockpit of the sister car.
Hamilton ran three laps longer and Verstappen's tyre advantage in the preceding laps meant the Red Bull regained the race lead. As the second stint progressed, Hamilton closed in on the race leader before Red Bull opted to pit first again on lap 30 - 26 laps from home.
This time Mercedes left Hamilton out eight laps longer, setting up his late charge that took him to the cusp of DRS range but no race-winning overtake.
"I think it was some interesting strategy games and great racing," said Mercedes boss Toto Wolff. "At the end, we thought we had a sniff at it but it wasn't enough, the moment you get close to the other car is difficult.
"They went for a super aggressive first stop. That was bold, we did that in Bahrain. They then covered it in the second stint and we thought that was enough to get them but they deserved to win today."
Hamilton concluded: "I thought for a second that we might be able to win the race but we have to wait until the next one."
If Austin had been considered a Mercedes stronghold, then the 'next one' is certainly a happy hunting ground for Red Bull - the Autodromo Hermanos Rodríguez in high-altitude Mexico City. Verstappen will inevitably start as favourite there on November 5-7 but, if this amazing yet unresolved 2021 title fight has told us anything, it is that predictions have become a mug's game.