Mario Andretti is "betting" on Sebastian Vettel getting on top of the new rules and believes Daniel Ricciardo is "one of the special talents."
This year's switch from V8s to 1.6-litre turbocharged V6 engines arguably hit Red Bull the hardest as their engine supplier Renault lost out to Mercedes.
Added to that, other regulation changes have affected the downforce of the cars, a move that Andretti feels has played a large role in Vettel's struggles.
Unlike last season when he won 13 grands prix on his way to a fourth successive World title, this year the German has only achieved two podium results in 11 starts, neither of which has been a victory.
"It's really interesting to see that," Andretti said of Vettel's struggles. "Sebastian would probably admit himself that he's had a tough time adjusting to this big change.
"He was so tuned in with more downforce and all that. He's missing that considerably and up to now it has shown. But I think it's getting better and I have no doubt that he will totally embrace it because his talent is enormous. But it's probably taken more time than he thought it would.
"He's a champion and that will show eventually, but I'm sure no one is more disappointed than he is at this point. He's totally dedicated - he's one driver that I think is totally focused on his job; he has no other distractions and that's all he cares about. He'll get it done, I'm betting on that for sure. But I'm sure he's frustrated at the moment."
As for his new team-mate, Ricciardo, the American reckons he has surprised everyone in the paddock, even himself.
Ricciardo is currently third in the Championship and is the only driver aside from the Mercedes pairing to have reached the top step of the podium, winning in Canada and Hungary.
"He's been fabulous," he told the official F1 website. "I mean, I'm sure that he has even surprised himself. He has been consistently quick and doing it very well.
"I've been watching some of his overtaking and it's just consistently perfect - it's really aggressive but really well-calculated. He's showing a lot of class this year and his character is nice too - always with a smile. He keeps himself very cool and calm and he's doing his things really well.
"You could tell going in [to Red Bull] that he had nothing to lose because he was certainly not expected to outshine Sebastian. But right from the beginning he took charge and he's still there. He's one of the special talents that you love to see now and then.
"It's also a good thing that Red Bull's 'farm team' [Toro Rosso] has produced two worthy talents. I love to see that, when talent is promoted from within."
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