Renault remains confident it can reduce the power deficit to Mercedes by half before the start of the season after two of the three pre-season tests.
The Mercedes-powered cars dominated the 2014 season and have looked like the strongest in the first two tests of 2015 so far.
Renault is still catching up after a difficult 2014, but managing director Cyril Abiteboul believes the current rate of progress means the French manufacturer will have reduced the gap to Mercedes by the season-opening Australian Grand Prix.
Abiteboul insists, however, that it is still hard to judge the pecking order.
"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," said Abiteboul.
"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."
Renault drivers covered over 12 grands prix distances - 3,800 kilometres - during the course of the Barcelona test.