Renault's engine technical chief Rémi Taffin believes the French manufacturer has a lot to be proud of this season as they have clawed their way back into the fight.
Formula 1's switch to V6 engines in 2014 heralded the rise of Mercedes, and the fall of Renault.
On the back of a wretched 2015 season in which Red Bull dissolved their partnership only to sign a new deal, Renault have made great strides forward this season.
It resulted in a victory for Red Bull at the Spanish GP with the team also replacing Ferrari as Mercedes' closest rival.
Speaking about Renault's progress with their engine, Taffin told GPUpdate.net: "I think not only I, but we are proud of what we have achieved, because it's not work you do in one day.
"When we sort of got out of the problems, the big problems we had early last year, we've been concentrating on our job, not being disturbed by what's going on on track.
"I think the guys back in the factory have done a really, really good job, because not only have we got the reliability back, but we've also got the performance in.
"Sometimes people talk about upgrades every two races and stuff like that, but you don't really feel or see it on track, but this time it was clear.
"I think that's the thing we should be proud of, because we did what we said we would be doing, which I guess is the most important."
Taffin, however, acknowledges that Mercedes' power unit remains the one to beat but says Renault are not aiming to match their unit, they are out to better it.
"I think if we look at every bit of information we've got, we know we're still behind Mercedes. We're getting close to Ferrari, but there are still some steps to make.
"I think what we see on track is we're now able to give our drivers an engine that is capable of fighting on track. Whether it is to overtake, defend or set a lap time, it's there. It's not like we've got a weakness.
"We know we have to work. We more or less know what gap we've got from the guys in front. But it's not the gap to the front we're concentrating on, it's actually the absolute power we will take out of the engine.
"It's not like we are targeting to be at the same level, we are targeting to be a higher level than the rest."
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