Vanthoor managed to wrest the lead of the six-hour contest away from home favourite Toyota with a bold move up the inside of poleman Mike Conway at the very start of the race.
With both Toyotas being compromised, dropping the two GR010 HYBRIDs that had locked out the front row down the order, Vanthoor was able to build a gap at the head of the field in the #6 Porsche 963 he shared with Kevin Estre and Andre Lotterer.
Vanthoor was able to hand over to Estre with the lead intact as the Toyotas lost time stuck behind the slower Ferrari 499Ps early on, but ultimately the superior race pace of the Japanese marque told as Estre was passed just shy of the four-hour mark.
In the end, Lotterer brought home the #6 machine for the final spot on the podium 48 seconds down on the winning #7 Toyota, and only 8.6s down on the second-placed #8 car.
Reflecting on the start, Vanthoor said he knew he had to take advantage of his strong launch, and was pleased that his car ended up leading for almost two-thirds of the race en route to Porsche's second podium finish of the season.
“I’ve been doing the starts all year and I like doing them, and after qualifying I was joking to Kevin and Andre about making a move [at Turn 1] to upset the Toyotas, because we’re not going to be able to really fight them,” Vanthoor told Autosport.
“At the start I got a good run and I thought, ‘f***, I need to live up to what I told them!’ It was quite close, but apparently nobody made the apex at Turn 1… but it put us in a good position, and I was surprised to be able to pull away as well.
“I was expecting the Ferraris to come at me, I was thinking I was using my tyres too much, but we had the pace at the moment. In the end, the Toyotas caught us, but we led more than half of the race, which is quite promising.”
Asked if he felt victory was possible after extending the lead to as much as 16s at one stage, Vanthoor replied: “Genuinely in the first half-hour, I was thinking, am I using my tyres too much? Are they being more conservative?
“But I was well within our targets, and the gap just kept increasing. It seemed to be going our way. But in the second stint I saw the Toyotas come back a bit.
“To be able to fight them that much was above what we expected.”
Porsche Penske Motorsport managing director Jonathan Diuguid called the #6 car’s lengthy stint in the lead “very satisfying” after a tough run of races since the team’s previous podium finish at Portimao back in April.
“It goes to show the team has made some steps over the summer break,” said Diuguid. “I think we made progress on the mechanical side of the car, also on software and understanding the tyres.
“I think that was a big part of our performance, especially in the first two stints. Our engineering group selected the right tyres whereas Ferrari was on the hards and Toyota had some hards on their cars as well.
“Once everyone figured that out, the true pace of the cars took over but I think that was what helped us get out in front.”
Diuguid also clarified that the #6 car’s early first stop, which put it slightly off-strategy compared to the two Toyotas, was due to not filling up the fuel tank fully for the start.
“That’s a procedural thing we need to figure out on our side,” he said. “But I don’t think it had a huge impact on the race result.”
