F1 legend Alain Prost says Renault now has "one of the best engines in Formula 1".

At the end of last year, Renault and top-three F1 team Red Bull parted ways. Renault now has a single customer, McLaren, in addition to its works team.

And 2019 did not start very well.

"The beginning of the season was difficult," team advisor and quadruple world champion Prost admits.

"But we always recognised that there were problems. We had problems with understanding what was happening with the tyres, and we also did not have reliability with the engine.

"It was an unpleasant surprise. This was a negative point, but also a positive because we managed to recover quickly."

Indeed, the latest car and engine upgrades have proved to be good steps for Renault, with McLaren and the works team fourth and fifth in the world championship.

"Now we can safely say that we have one of the best engines in Formula 1," Prost told Le Figaro newspaper. "Nevertheless, we still need to improve to be able to compete with Ferrari."

However, Prost thinks catching up with Mercedes, Ferrari and Red Bull in the chassis department will not be easy.

"We may be able to beat Red Bull here and there, but it's simply impossible to catch up with Mercedes and Ferrari this season.

"If the gap today is a second, then we need to reduce it to half a second by the end of the season," said the famous Frenchman.