Stoffel Vandoorne has said that the ball is now in McLaren's court after the British team dropped Honda at the end of last year.
In 2018, the team will use identical engines to race winner Red Bull and the Renault works team.
"Red Bull proved last year that you can win with a Renault engine," Vandoorne told Belgian newspaper Het Laatste Nieuws.
"So you could say that the ball is in our court now that Honda is no longer here."
However, the 25-year-old Vandoorne said that he is confident.
"The atmosphere is excellent and there is a much more direct contact with the Renault people than there ever was with Honda," he said.
"There are now far fewer problems that we have to deal with and therefore lose time and energy on."
The downside is that while McLaren insisted its 2017 chassis was good, engineers had to work hard over the winter to accommodate the very different Renault power unit.
"The guys tell me that they had time to do everything that was needed. And as far as those adjustments are concerned, it was quite easy," said Vandoorne.
"You can safely say that the new car is a development of the chassis that we had already, which was excellent. So I do not think we have a disadvantage compared to the other teams that did not change their engine."
Vandoorne is therefore confident that, after McLaren's three very bad years, better times are finally on the horizon.
"In principle we should do well, because our weakness is gone," said Vandoorne.
"But this is Formula 1 and only the stopwatch will tell. At least we will have the advantage that we can really test this time in Barcelona, in contrast to last year when we were constantly in the garage."
As for reports cold and wet conditions could be descending on Barcelona, he said: "I do not want to think about that. The vibe in the garage is very positive."
The new season gets underway with the Australian Grand Prix in a month's time.
