Renault Sport admits they still have ground to make up to Mercedes in terms of their power unit, but they are confident they will reach their target.
The French engine manufacturer was found wanting last year and it meant the Mercedes-powered teams were able to steal a march on their rivals with the new turbocharged 1.6-litre V6 engines.
Renault, who is supplying power units to Red Bull and Toro Rosso this year, appear to have made up some of 10 percent power deficit that they had last year, and managing director Cyril Abiteboul feels they will be halfway to their target when the season gets underway on March 15.
"Our main objective in Barcelona, which was outlined and shared with our partners, was to accumulate as many kilometres as possible in order to continue improving reliability. Without a single major issue for either team it's an area that we're completely satisfied with," he said.
"Equally, the test validated a certain number of measures implemented since Jerez, which have proven conclusive. On a human level it's also been satisfying to see our technical staff working ever more closely with our partner teams. The results have been very positive.
"Regarding performance, of course it's still a bit early to make a proper judgement as it's always relative and we don't know what the competition is doing. On our side, we didn't spend the test chasing lap times. Such aggressive and uncompromising development programmes, both in terms of chassis and the Power Unit, as well as new parts arriving at the last minute, also make it difficult to draw conclusions.
"Saying that, we're still confident of achieving our target: reducing our Power Unit deficit to Mercedes by half for the first grand prix. Our reinforced partnership with Red Bull is also moving in the right direction, and the overall situation looks encouraging."