Lando Norris' championship hopes were dealt a hammer blow after he was handed a controversial five-second penalty to finish behind rival Max Verstappen following a compelling US Grand Prix.
As Charles Leclerc raced to an impressive win at Austin's Circuit of the Americas, pole man Norris was only fourth - one place behind Verstappen - to leave him 57 points adrift in the title race with only 146 points to play for across the concluding five rounds. Carlos Sainz took second to complete a Ferrari one-two.
Norris spent the final dozen laps crawling all over Verstappen's gearbox in a thrilling conclusion, and he eventually made the move stick on the 52nd lap.
However, the stewards quickly launched an investigation into the pass, and Norris was adjudged to have run off the track. Norris was penalised, and although he crossed the line in third, four seconds ahead of Verstappen, his sanction dropped him back, in what could prove a pivotal decision in his championship quest.
Norris might have hoped he had banished the first-lap demons which have so far plagued his championship bid.
Up until the previous round in Singapore, Norris had failed to end the opening lap in the lead on any of the five previous occasions he has started from pole. Under the lights of the Marina Bay Circuit, Norris finally ended the hoodoo before going on to claim the most emphatic win of his life.
But here, in the Lone Star State, Norris was left to rue another poor getaway.
There was nothing wrong with the McLaren man's initial reaction time. As he roared up the hill there was clear daylight between Norris's McLaren and Verstappen's Red Bull.
But Norris left the door open for Verstappen at the left-handed corner and the triple world champion did not need a second invitation.
Verstappen was more aggressive on the brakes than Norris to slingshot ahead of his rival. Norris ran off the track and was soon on the radio to take aim at Verstappen's driving.
"He clearly pushed me off," protested Norris. "He had no intent on making the corner. He had to go off the track as well. I had to avoid crashing into him and him into in me. He went in so hard he went off the track, same as Budapest, it was identical."
At the Hungarian Grand Prix, an investigation was launched into Verstappen's first-corner conduct, and he was advised by his Red Bull team to give the place back. Here, there were no such orders.
McLaren boss Zak Brown called Verstappen's move a "divebomb" but both his and Norris' protests fell on deaf ears. The stewards did not even note the incident, let alone launch an investigation.
Leclerc started fourth but took advantage of Norris and Verstappen tripping over one another to assume the lead. Sainz slotted into third, with Norris now fourth.
Lewis Hamilton has won a record five times in Austin, and six in all in the US, but the seven-time world champion has endured a weekend to forget.
He qualified seventh and finished sixth in the sprint before qualifying only 19th for the main event. Hamilton made his way up to 12th but his race suffered a premature end when he lost control of his Mercedes at the penultimate corner on lap two. With his Silver Arrows beached in the gravel, Hamilton's race was run. "Sorry, guys", he said.
Out came the safety car and Leclerc made no mistake at the re-start to keep Verstappen at arm's reach, with Norris unable to make any impression on Sainz's Ferrari.
By the start of lap 24, Leclerc's lead over Verstappen was 10 seconds and his team-mate Sainz was also on the move. Pitting four laps earlier than Verstappen, he was able to jump the Dutch driver when he stopped on lap 25.
Norris stayed out until lap 31 in the hope of gaining a tyre advantage for the climax of the race. When he left the pits he was 6.6 sec behind Verstappen and he was able to half that advantage over the next half-a-dozen laps to provide him with hope.
"These tyres just aren't good," complained Verstappen. "I can't brake. I can't attack anything."
Norris was taking chunks out of Verstappen's advantage and by the start of lap 44 he was one second behind and within DRS range.
With nine laps remaining, Verstappen was defending for his life as the two championship contenders went wheel-to-wheel. Verstappen was deploying all of his brilliance to keep Norris behind.
On lap 51, Norris thought he had got ahead coming out of Turn 13 but Verstappen again clung on, in what was proving to be a defensive masterclass for the ages.
Then on lap 52, Norris drew alongside Verstappen on the 215mph drag to Turn 12. Verstappen held the inside line, and Norris completed the pass, albeit off the track.
Norris asked his team whether he should hand the position back, but they urged him not to, believing that their man was ahead at the apex of the corner, but the stewards took a different view.
Norris' team-mate Oscar Piastri finished fifth, one place ahead of Mercedes' George Russell.
