Red Bull chief Christian Horner believes Renault offers his team the best chance of success in Formula 1, despite the problems the French manufacturer has been going through.
Renault has had a disappointing start to the 2015 season to follow up a tough 2014 which was dominated by Mercedes and its power units.
Red Bull is yet to finish higher than sixth this year, and the reliability of Renault's engine has left the team on the verge of starting to serve penalties.
In reality our best chance is with Renault - and vice versa.
The French car maker has admitted it is still considering its future in F1, not ruling out leaving the sport, a situation that Horner said could lead to Red Bull having to pull out too because it would not have an engine supplier.
Red Bull has a contract with Renault until the end of 2016 and, despite the troubled times, Horner is convinced the partnership is beneficial for both.
"In reality our best chance is with Renault - and vice versa," Horner told the official Formula 1 website.
"We have won 50 grands prix and eight world championships together - so sometimes frustration boils over.
"It is in Renault's interest as much as in ours to sort the current issues out as quickly as possible."
Five engines not enough
With Red Bull's Daniel Ricciardo already using the fourth of his four allocated engines, the Australian looks set to start getting penalties soon.
Although Horner said the teams have agreed to increase the allocation to five - a move that is yet to be ratified by the FIA - he is convinced even that will not be enough for Red Bull.
"It is frustrating. For sure we are going to use more than four - we've used three in three races - so the chances of us staying within the limit of four is close to zero," he added.
"The teams agreed unanimously in Malaysia to introduce a fifth engine, but the engine penalties will affect others too - not only us.
"For us we would need that number to increase to seven, eight or nine engines for the season. Unfortunately these are the rules and we are not looking great within these rules.
"Hopefully these rules will become more realistic in the future."