Max Verstappen cliched a second title in extraordinary circumstances after dominating a Japanese Grand Prix truncated by heavy rain.
Verstappen headed Sergio Perez in a Red Bull one-two after Ferrari's Charles Leclerc, who crossed the line second, was penalised for cutting the track and gaining an advantage on the last lap.
There was confusion after the race as to whether Verstappen had done enough to tie up the championship, because it was not immediately clear whether full points would be awarded for a race that ran just over half distance.
But governing body the FIA said that reduced points only applied if a suspended race could not be resumed.
Even Verstappen asked: "Are you sure?" when he was told he was champion, reflecting the historical precedent that reduced points are awarded in such circumstances.
But it seems that this protocol was inadvertently left out of the rules when they were rewritten over last winter following the controversial Belgian Grand Prix, when a result was declared despite no racing taking place.
There can, however, be no question marks about the validity of Verstappen's championship, after he secured his 12th victory of the season in the same manner as he has taken control of the championship, by being a class apart from everyone else in his Red Bull car.
The race was marred by a controversy over officials deploying a recovery vehicle on to the track while cars were still running after a crash on the first lap.
Drivers and team bosses united to call the decision from race control "unacceptable", eight years after Jules Bianchi lost his life after crashing into a tractor on track
The race was stopped shortly afterwards, leading to a two-hour delay while officials waited for the persistent rain to ease sufficiently for racing to resume.
When it finally did, Verstappen and Leclerc initially pulled away from the rest of the pack, but as the laps ticked by Ferrari's tyre problems reared their head.
Leclerc dropped back from Verstappen and Perez began to reel in the Ferrari. Leclerc held him off for several laps and looked to have done enough, only to lock up at the final chicane on the last lap and cut the corner.
Leclerc held Perez off to the line, but was deemed to have gained an advantage by going off track and was demoted back behind.
Behind them, Alpine's Esteban Ocon held off Lewis Hamilton's Mercedes for the entire race, with Aston Martin's Sebastian Vettel doing the same to Fernando Alonso's Alpine.
Alonso made a stop for fresh tyres with just 15 minutes of race time remaining and dropped to ninth, reclaiming sufficient ground to finish the race right on Vettel's tail, but unable to pass.
Mercedes' George Russell climbed up to eighth from 13th, after being delayed by being stacked behind Hamilton in the pits when the field changed from wet to intermediate tyres, and the final points when to Williams' Nicholas Latifi and McLaren's Lando Norris.
More to follow.