The 2018 Formula One season has been full of drama and controversy from the start - which must be welcome timing for owners Liberty Media who were worried that there might be a lack of it.

Sunday's Spanish Grand Prix in Barcelona was no exception, kicking off with a three-car crash that saw Haas' Romain Grosjean career across the track and take out his rivals.

At the other end of the race, however, Lewis Hamilton eased to a second consecutive victory that helped him pull clear of Sebastien Vettel in the standings.

However, even in qualifying, Mercedes and Hamilton were accused of benefitting from a decision by tyre manufacturers Pirelli.

Pirelli brought in thinner tyres for the GP as they were worried the heat in Barcelona could cause problems with the thicker variant teams had been using.

It was a decision welcomed at Mercedes, but not necessarily elsewhere, with some claims of conspiracies among the backlash as it was perceived to have been a deliberate ploy to help out the German manufacturer.

Ferrari believed that the decision cost them race pace on Sunday and took the opportunity to test out the difference for themselves during testing on Tuesday in Barcelona - and Vettel believes they have had a final verdict on the decision.

"I think it's pretty straightforward," said Vettel.

"Obviously you don't get the chance to revisit this kind of decisions that are made, but we did it today and the result is that if we had had the normal tyres on Sunday, it would have probably been worse, so it was the correct call.

"It was our fault for not having the same tyre wear or life as other people."

Vettel took both of the opening two GP's this season but a trio of sub-par results have seen him fall away from rival Hamilton.

Ferrari need to make up ground on the Brit and their driver believes testing has proven to be very helpful in that regard.

"It's good to have the test to be able to compare and I think we have some ideas," he said. "Now it's up to us to turn those ideas into reality.

"As I said it was good in terms of timing, coming from a poor weekend for us, we were not quick enough and more than not being quick enough we were struggling to make the tyres last - these things have a link - so it was good to have a possibility to revisit it and now it's up to us to take action."