The pole-sitting Toyota of Mike Conway, Kamui Kobayashi and Jose Maria Lopez was on target Sunday to claim the Japanese manufacturer's fourth straight Le Mans 24 Hour crown with six hours left on the clock.
As dawn broke over the famed La Sarthe Circuit Toyota's number seven car narrowly led from its sister hypercar and winner of the last three editions of Kazuki Nakajima, Sebastien Buemi and Brendon Hartley.
But their advantage grew to around three minutes after 276 laps when with Buemi at the wheel the number eight car slowed to a halt wih suspected gearbox and refuelling trouble.
After a reset Buemi was back up and running, albeit a lap behind.
In third, four laps adrifspt, came the elite category rival Alpine of Andre Negrao, Nicolas Lapierre and Matthieu Vaxiviere.
The Alpine had muscled back into podium contention after slipping to sixth after night fell when with Vaxiviere at the wheel, the car lost control on the wet surface and ended up in a gravel trap.
- All-female crews -
Under a minute behind came the Glickenhaus of Pipo Derani, Franck Mailleux and Olivier Pla, the team backed by US film director and businessman James Glickenhaus.
The fifth and final entry in the hypercar category, the second Glickenhaus, was placed eighth.
The 89th edition of motorsport's mythic endurance test had got off to a soggy start with heavy rain rendering the circuit treacherous.
In a break from tradition organisers had allowed the 61 competitors to do three formation laps to get used to the wet track.
A merciful dry night kept the windscreen wipers unemployed but showers were forecast again as the race neared its conclusion at 16h00 local time (1400GMT).
Die-hard fans are back this year after Covid-19 forced organisers to hold last year's race behind closed doors, although the crowd is capped at 50,000, a fifth of the usual 250,000 who traditionally descend on the circuit.
They witnessed drama at the start when Buemi starting from second on the grid was involved in a collision with a Glickenhaus during the opening lap.
The race then required the entry of the Safety Car when a heavy shower saw multiple cars come off at Porsche Curves and the Dunlop Chicane.
Kobayashi, who drove for Toyota and Sauber in his F1 career, is praying the fickle Le Mans gods spare him the ill-luck that kyboshed his chances of likely victory in the last two runnings.
For the second time there are two teams featuring all-female crews.