Vettel calm about Red Bull reliability

The German, whose 2009 title campaign was hampered by retirements, caused a red flag when he stopped during a race simulation at Catalunya this afternoon, but said he had just been playing it safe - as the team has throughout the winter.

"Obviously you don't want to stop, but sometimes you don't want to risk any damage and it's better to shut the car down if you see something wrong on the data," Vettel said.

"Obviously in the race you'd try to continue, so sometimes it's nothing bad but it's better to shut the car down and bring it back and have a look. But obviously ideally you keep on running and you park the car in the garage and not somewhere on the circuit.

"But I don't think we have to fear reliability issues yet. It looks good. Everything that happened I think is normal. We have a new car, new parts, everything is a bit new and slightly different in design.

"The cars have changed, a bigger fuel cell but also lots of new small parts, everything has changed slightly and sometimes you realise you should've done it a bit differently, but you are on top of those things very quickly."

Despite this week's times suggesting that Red Bull and Ferrari might have edged slightly clear of McLaren and Mercedes in the battle at the front of the field, Vettel was unwilling to make predictions yet.

"I think today Ferrari looked extremely quick," he said. "Probably this morning it was [running] lower fuel - if you go in the 1m20s you have to be on low fuel - and also on the long run [Fernando] Alonso was quite quick. I don't know what was going on with McLaren and Mercedes today. I haven't looked that closely but they didn't seem to be that quick today.

"But you look at the other days at Jerez and you look at yesterday and probably the next two days as well and you'll have another surprise. Sometimes it shifts. But I think overall it will be extremely tight. All four teams are big teams and they have proven many times in the past that they are competitive. So it will be a close fight.

"Obviously I would love to tell you that we are a second ahead of everyone, but at the moment at least it's not the case."