Sergio Perez beat pole-sitter Charles Leclerc at the start to win a wet Singapore Grand Prix for Red Bull on Sunday while team-mate Max Verstappen must wait at least one more week to clinch back-to-back world titles.
Perez got his second season and fourth career victory ahead of the Ferrari duo of Leclerc and Carlos Sainz.
However, Perez was under investigation from race stewards for possible safety car infringement.
A possible five-second penalty would do him no harm as he won by 7.4 seconds but 10 seconds added would see him drop to second place, with Ferrari reportedly believing in two infringements.
Verstappen had to be content with seventh in a race which did not go over the full 61-lap distance but ended after two hours due to slower lap times owing to the conditions plus several safety car phases.
The Dutchman could have wrapped up the title with victory and other results also in his favour.
But Red Bull's failure to give him enough fuel for a final fast lap in qualifying forced him to start from eighth. He moved up to fifth in the race but a driving error then saw him drop back again.
He is now 104 points ahead of Leclerc with five races left, and a second chance to clinch the title prematurely comes next Sunday in Japan.
"It was certainly my best performance. I controlled the race," Perez said in the post-race interview. "The last three laps were so intense. I gave everything today."
Looking at the investigation, he added: "I have no idea what's going on, they just told me I was under investigation and to increase the gap."
Leclerc said: "The bad start put us on the back foot and it was a really difficult race after that."
The start of the race was delayed by an hour after heavy rain and the track had not fully dried once the action got going, with all drivers using intermediate tyres first.
Perez won the sprint into turn one from pole sitter Leclerc while Sainz robustly moved into third past Lewis Hamilton's Mercedes.
Verstappen lost four places down to 12th after lap one while Sebastian Vettel shot up five to eighth in his Aston Martin.
Perez and Leclerc pulled away and there were no changes at the top through one safety car and several virtual safety cars.
Six drivers had to retire for various reasons, including Alpine's former world champion Fernando Alonso who was competing in a record 350th grand prix, one more than former Finnish great Kimi Raikkonen.
Hamilton's podium bid ended in the 33rd lap when he hit the barriers but was able to continue to finish ninth after another mistake.
Leclerc started the pit stops for dry weather slicks in earnest with everyone else swiftly following before Verstappen locked up while trying to pass McLaren's Lando Norris into fourth, flat-spotting a tyre which which sent him right back to the pits and ended his podium ambitions.
Up front Leclerc hunted down Perez but the Mexican withstood the pressure to win - only to face an anxious wait over what the stewards will decide.
