Sebastian Vettel says a straightforward comparaison test between Pirelli's standard tyres and its Spanish Grand Prix modified rubber revealed that Ferrari's issues were chassis related.
The Scuderia's relative under-performance in last weekend's race led Vettel to suggest that his lack of pace was linked to Pirelli changing the tread depth of its tyres to accommodate the Circuit de Catalunya's new asphalt.
Tuesday's running in Barcelona however told the German driver a different story.
"I think it's pretty straightforward," he said.
"Obviously you don't get the chance to revisit this kind of decisions that are made [very often], 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."
The Scuderia took the opportunity to work on its deficit and the issues it suffered on Sunday.
"It's good to have the test to be able to compare and I think we have some ideas. Now it's up to us to turn those ideas into reality," he added.
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.
"Obviously it looked like from the outside they [Mercedes] had a stronger weekend, without any big issues, but we need to look at ourselves, focus on our car and our problems, so we'll be stronger again."