This year Porsche returned to the top flight of the WEC for the first time since 2017 with the 919 Hybrid LMP1, partnering up with US squad Penske to run its two-car works programme.
So far its best result has been a third place at the Portimao 6 Hours with the #6 car crewed by Vanthoor, Kevin Estre and Andre Lotterer.
The #6 entry had also been in podium contention at Spa before it shut down on track in hour three and couldn't restart, then all three works-run cars endured troubled runs last time out at the Le Mans 24 Hours as Ferrari ended Toyota's winning streak.
Speaking to Motorsport.com ahead of this weekend's Monza round of the WEC, Vanthoor explained that he anticipated Porsche success to come sooner but still expects it is possible to emulate its IMSA SportsCar Championship arm that took the 963's maiden competition win at Long Beach.
He said: "It's two names, Porsche Penske together. That's my mindset; if the best doesn't have success together, then I don't know.
"For me, it's just destined to have success at one point. It just will maybe take a little bit longer than everybody had hoped for.
"That's the reality where we are. We just need to understand how we can quickly be there where we want to be and then win races."
Vanthoor explained that he expects the programme will yield stronger results from the natural knitting together of the two arms of the team.
"I think it's a question of time for everything to gel together," he said. "We are understanding the car a little better, it's improving.
"It's a complex car, it's a complex team as well because you've got two giants together. Everybody needs to find their place.
"I guess it just takes time, which I'm seriously convinced that it will be okay. But it was maybe more of a hurdle than we expected in the beginning."
Vanthoor added that he feels "very comfortable and very confident in the car" upon his adaption to prototype racing, having focused on GTs for the bulk of his career.
"I do feel like I arrived there where I wanted to be," he said.
"There's definitely still room for improvement, but I'm enjoying it as well. I like driving these cars, I like being part of this team, these races.
"I would like it more if we're winning, but that will come."
