Renault's F1 engine is now "very close to Mercedes", according to James Key.
He is the technical director at McLaren, the only team apart from Renault's works outfit to use the French marque's engines in Formula 1.
Renault has lagged behind the leading engine manufacturers in the 'power unit' era, but Key said the situation changed in 2019.
"We saw that the Ferrari was a little ahead, but the competitiveness of the Renault engine was quite good and very close to Mercedes actually," he told El Mundo.
2020 will be the third and final year of Renault power for McLaren, who are switching to Mercedes engines for 2021.
Key, however, says that in the wake of the Honda debacle, McLaren has been happy with Renault.
"One of the positives of 2019 was that Renault took a very obvious step forward and improved the speed on the straight. That was definitely part of our improvement," he said.
Key also says the other engine manufacturers in F1 are now closely matched.
"The times when the engines were very different basically disappeared last year," he said.
