Renault admits it made a poor start to the season in terms of power unit reliability but is encouraged by its subsequent gains through the year.

The first four races this season were each marked by at least one Renault works car retiring, and it wasn’t until round six that all four of the Renault-powered cars – also including McLaren – finished a race. Japan marked the seventh time that all four went the distance, and engine technical director Remi Taffin said good progress has been made from a reliability perspective during the season.

“We’re pleased with the level of performance we have, but we’re not stopping there,” Taffin said. “We have to work for next year and the year after. We’re happy to get this level of performance in our car and also in the way we are cleaning up our reliability after a poor start of the season in that respect.

“There’s room to improve and we’ll be aiming to do that. We introduced our last engines in Spa and Monza, and we’re focused on delivering for 2020 and 2021 and reaching high level performance and reliability.”

The two Renault drivers will run older power units during Friday practice at the remaining races after taking their latest upgrades at the end of the European season, but Taffin is hopeful of a strong showing in Mexico this weekend, where Renault-powered Red Bulls won on each of the past two occasions and Daniel Ricciardo took pole last year.

“Mexico is like a performance damage limitation event; we don’t primarily design the car to be Mexico specific, we only ensure we minimize the effects of the altitude,” he said. “During the last few years, we’ve been relatively competitive there.

“In terms of the power unit, we know the engine can’t run at its maximum and the turbo is not capable of compensating for the less dense air. We can preempt what to expect in Mexico on the dynos in Viry, and we’ve been racing there for a few years now and know what to expect from our package. We will then find out where others are.”