Alain Prost thinks Red Bull can be a "big challenger" to Mercedes for the rest of 2016 and that its recent resurgence is validating the good work done by Renault since the winter.
Renault made a big step with its engine over the winter and delivered another performance boost with its most recent engine upgrade in Monaco, which helped Red Bull to its first pole position since 2013 in Monaco. Renault's factory team is languishing off the pace but is still in a rebuilding phase after purchasing Lotus over the winter.
Though Red Bull's TAG Heuer-branded engine is a reminder of its spectacular rift with Renault last year four-time world champion Prost thinks it can only be good news to see the Milton Keynes outfit putting pressure on Mercedes while the factory team is uncompetitive.
"They could be a challenger, maybe a big challenger, for Mercedes, definitely," Prost, a Renault ambassador, said when asked about Red Bull's chances in 2016. "But I don't think Renault can do much more for the engine, but for sure there will be some more improvement...
"But [Renault] are very happy ... unless they are going to become competitive [against Red Bull], which is not today, they are very happy to see the engine winning and Red Bull to be a contender. I'm not jealous at all, for sure!"
With Renault not expecting to be truly competitive until 2017 or 2018 at the earliest Prost thinks Red Bull's rise up the pecking order is giving the French manufacturer a glimpse of what is possible in future.
"I think it's a very positive thing, in this situation. It's a constructor team, so you have an engine and chassis together now, so it can be a positive fight or competition. At least you know that the engine is working well and can be very good making the people making the engines, very good for the image, very good for Red Bull.
"It is very positive for everyone because you can concentrate and it gives you a good vision to concentrate on -- you can say 'this part is working, so now we can do even better'. Then we can concentrate, it's so much work so it's good to have one element we know is going to be OK, it's very positive."
Renault and Red Bull nearly split last year after a second consecutive season lacking performance and reliability on the power unit side. Prost says the recent engine gains are positive when viewed in the context of Renault's struggles in 2014 and 2015.
"I think everybody can be a bit surprised because it is typical racing. It is quite surprising considering that for sure the last two years were quite tough. But that is typical F1, things can change and sometimes what you get what you are paying for: a decision - or no decision - two of three years before. So it is a very good surprise, very positive."