(Reuters) - Formula One champions Red Bull called an early end to a nightmare first pre-season test in Spain on Friday and focused on fixing the problems before their next track outing in Bahrain in two weeks' time.
The sport's dominant team said in a statement that continuing mechanical issues with the new RB10 car, unveiled only on Tuesday, had forced them to stop and start packing up.
"It's been a very difficult test," said principal Christian Horner. "We have had numerous Renault issues as well as chassis cooling issues, which have affected our progress.
"However, despite the lack of mileage, what we have managed to learn shows that the problems should be solvable for the next test in Bahrain."
The season starts in Australia on March 16.
Quadruple world champion Sebastian Vettel went home on Wednesday after completing just 11 laps in two days while Australian team mate Daniel Ricciardo managed only three on Thursday.
Other Renault-engined teams have also had problems while those using Mercedes and Ferrari units have managed to get good mileage.
Red Bull have been Formula One champions for the past four seasons, with Vettel wrapping up his fourth successive drivers' crown last year with three races to spare.
The German won 13 races in 2013 including the last nine but his chances of a 10th in a row in Melbourne in March are looking far less likely.
Ricciardo did seven laps on Friday with the team fixing problems as they emerged.
"Every time Daniel went out we made improvements to the control of the engine. We were also making fixes to the issues that have arisen from our side and we have made progress there," said the team's race engineering co-ordinator Andy Damerum.
"However, we then discovered a mechanical issue with the car and after investigation it became clear we would not be able to fix this in time to run in the afternoon, so the decision was taken to retire early.
"Two weeks is a long time in Formula One and we, and I'm sure Renault, will work flat out now to solve the problems we've been having."
(Reporting by Alan Baldwin, editing by Pritha Sarkar)