Sebastian Vettel defended Ferrari's Spanish Grand Prix strategy on Sunday after a second pitstop dropped the Formula One title challenger to fourth place and 17 points adrift of Mercedes rival Lewis Hamilton.
The German, winner of the season's first two races, had been second before coming in for a fresh set of tyres while Hamilton won with one stop from pole position.
"We couldn't make the tyres last, so for us it was clear we come in again. I think it was the right thing to do," said Vettel.
"We were going through the tyres too quick and therefore we were not able to stay out for another 23 laps. Even in the end , with the fresher set I wasn't able to attack until the end," he added.
Vettel had pitted when the virtual safety car was deployed to slow the field, something that had played in his favour at previous races.
Instead, both Mercedes' Valtteri Bottas and Red Bull's Max Verstappen were able to get ahead, with Vettel also losing time with an error.
"Obviously, you have to slow down, the tyres are getting cold and it's my mistake. I came into the box maybe a bit hot -- well, cold with the tyres -- and overshot the position," he explained.
"And then the guys (mechanics) have to reshuffle and I think that cost us a bit of time. We had some traffic in the pitlane as well."
The race was the third in a row that Vettel, stuck on 49 career wins, had finished off the podium. Two weekends ago in Azerbaijan, the four-time champion was also fourth and in China before that eighth.
Pirelli had reduced the tread depths of the tyres used at the smoother but grippier Circuit de Catalunya to reduce the risk of overheating but had said the
Ferrari clearly had more problems than Mercedes making them last, however, but Vettel was not making excuses.
"One, we were not quick enough. If we are not able to see that then we are more than blind," said the German.
"Second, I think we struggled a little bit over the course of the weekend with the tyres. They changed, but they changed for everyone.
"Third, I think it was a poor weekend in terms of reliability. Kimi (Raikkonen) had an issue with the engine yesterday, had to change the engine today and obviously retired in the race."
Grosjean gets three-place grid penalty for Monaco
French driver Romain Grosjean will have a three-place grid penalty for Formula One's showcase Monaco Grand Prix after triggering a multi-car collision in Spain on Sunday.
Race stewards also handed the Haas driver two penalty points.
Grosjean took out Renault's Nico Hulkenberg and Toro Rosso's Pierre Gasly when he spun his car across the track in a cloud of smoke at turn three on the opening lap of the Spanish Grand Prix.
"He spun and it's very unusual to see a car light up its rear wheels like that on the first lap of a race, when there's another 10 cars to come," race director Charlie Whiting told reporters.
Grosjean, who started 10th, told stewards he feared his momentum was going to take him to the centre of the track so he applied power to try and cross over to the right side and get out of the way of others.
"There's not much to say. I lost the rear end in turn three and I just spun. If you look at the footage, I had wanted to avoid contact with my teammate," said the Frenchman.
"Kevin (Magnussen) had a bit of a wobble, I lifted off the throttle, and then the car just went. I'm sorry for the others that were involved -- there wasn't much I could do once the car went."