Renault head of track operations Remi Taffin believes the engine constructor's power units will be approaching peak performance at this week's Chinese Grand Prix.
After a disappointing Bahrain Grand Prix earlier this month, where Red Bull managed only a single top eight berth, Renault were reminded of how far they currently are behind the Mercedes-powered teams.
Speaking to ESPN ahead of this week's race in Shanghai, though, Taffin revealed that a big improvement will be visible in China with Paddy Power backing Red Bull to rebound.
"Overall we're looking forward to China - while we know it's still an uphill battle, we feel we have hit our stride now." Taffin told ESPN.
"While we know that the others are still ahead, we have made some good progress in the last two races, both in reliability and driveability, particularly in race modes.
"At the test in Bahrain we tested several new software modes that will see us closer to the limits of the Power Unit than before. In the past three races we have been some way from the edge of the performance envelope but these new modes should see us running more to the extreme. The drivers should feel improved driveability and it should also give us greater life from each part."
Taffin conceded that the Mercedes engines, which are dominating the odds with F1 bookmakers, probably still has the edge over their Ferrari and Renault counterparts.
He is, however, confident that their race package is vastly improved.
"Likewise we have been working on the energy management per lap, particularly in the slow corners. We know we are missing out on the straights but these new steps have given us greater traction in the turns, which should in turn extend tyre life and give greater flexibility on strategies. In fact the greater part of our work has been concentrated on race modes and performance as this is where we believe the bigger steps can be taken, rather than in qualifying," he continued.
"All of these improvements should put us a bit closer to the front in China. Of the first four races, it is one of the most difficult. The long straight is of course the major feature of the circuit, but we believe the steps taken in testing will make us less vulnerable.
"There are also some tricky mid to slow speed corners in Shanghai such as the first 'snail' corner that tightens back on itself. This and the two hairpins give some opportunity for the MGU-K to recover energy under braking but the focus for energy recovery will be on the MGU-H and that long straight."