Sebastian Vettel tests his new machine in Jerez on January 29.

Red Bull team principal Christian Horner is confident there are no major problems with this season's car despite its below-par performance during the first pre-season testing in Jerez last month.

Red Bull, which has won the constructors' championship for four years in a row, completed a dismal 21 laps in its new RB10 car, while rivals Mercedes managed over 300 in four days of testing at the Spanish circuit.

“There's a few things we needed to tighten up on our side but nothing major and obviously Renault have some issues that they are tidying up as well,” Horner said in an interview with Sky Sports.

“But these cars are so complicated that even small problems can cause big failures.”

With a host of rule changes being introduced this season, including new 1.6-litre V6 engines fitted with complicated energy-recovery systems (ERS), Red Bull engine supplier Renault has struggled with overheating.

Adrian Newey, Red Bull's chief technical officer, has gone back to the drawing board in search of a solution and that has left Horner uncertain of how the car will perform at next week's test in Bahrain.

“Obviously, there's quite a bit to do but there's still a fair bit of time before the first race,” he said.

“The Bahrain test next week is an important test and we are working very hard at both Renault and Milton Keynes.

“We don't want another test like Jerez but that's what testing is for - you sort your problems out so as not to have them at the races.”