Formula One world champion Sebastian Vettel was left frustrated for a good part of the fourth and last day of testing in Jerez on Friday when his car fell victim to electronic and mechanical problems.

After two laps the 24-year-old German had to steer the RB8 into the Red Bull pits for what extended to a break of more than five hours, however he hit back later with the day’s third-fastest time, while Ferrari’s Fernando Alonso set the pace.

Vettel, who had the best overall average on Thursday, was sanguine as mechanics and engineers worked hard on the car before eventually initially discovering an electronics defect.

A new attempt to start was then broken off in the pit lane when the car developed an engine problem and had to be pushed back.

“That’s all part of the testing, it’s the reason we’re here,” said Vettel. “Of course, we would like to drive a bit more but there is nothing you can do about it.”

While other teams enjoyed a midday break, the Red Bull mechanics decided to change the Renault engine, which last year had caused virtually no problems for the team.

Despite the problems Vettel managed to get in 50 laps by the end of the day, finishing third quickest just ahead of Britain’s Lewis Hamilton in a McLaren.

Vettel was that he was not the only driver in the pits. Alonso’s Ferrari also needed some tweaking – although the Spaniard had by then clocked the fastest time of the day, 1 minute 18.877 seconds. Toro Rosso driver Jean-Eric Vergne was second quickest.

Nine of the 12 Formula One teams were in Jerez for the testing ahead of the 2012 season, with Mercedes the most notable the absentees.

After Jerez the next tests are from February 21 to 24 at the Circuit de Catalunya near Barcelona. Further tests follow from March 1-4 before the opening race of the season, the Australian Grand Prix on March 18.