Sebastian Vettel says he made the call to switch tyre compounds ahead of his final run in qualifying for the Spanish Grand Prix.

The Ferrari driver had been quickest in Q1 and Q2. But he used a harder tyre compound for his final run in Q3 which left him third on the grid.

Vettel said he was “pretty happy with the lap” at the end of the session but had been confused by his first run on the super-soft tyres in Q3.

“It was a bit confusing because Q2 was really plain sailing. The car was pretty good on the soft tyres, I had a couple of tenths in hand, I knew come Q3 we had something in the pocked which was good.

“But then on the super-soft first lap it just didn’t happen. I locked up into turn one and I never got the grip that I was looking for.”

That prompted his decision to put the harder soft compound tyres on. “It was straightforward because I had such a good feeling in Q2,” he said.

“I asked and we decided to go back o the softs and I think that was the right call. The lap was good. Maybe there was a tiny bit but not enough to get to the first row.”

Mercedes locked out the front row of the grid for the first time this year while Vettel’s run of three consecutive pole positions came to an end.

“I think we need to admit that they were just a bit quicker today,” said Vettel “For tomorrow though I think we should be in the mix.”

The Ferrari driver believes Mercedes have recaptured the form they showed at the beginning of the season.

“Looking back you have to admit that the last two qualifying sessions, they lost something. If they got that back it doesn’t necessarily mean that they found something, it’s just that they were back to normal. At the start of the season they were very strong in Australia and then we took over but they were struggling.

“Tomorrow it will be very close between the top three teams. I expected Red Bull actually today would be faster in qualifying. I don’t know what happened to them but for sure tomorrow it will be tight.”

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2018 F1 season