Valtteri Bottas said he "just about got away with" a risky strategy call which allowed him to hold off Ferrari's Kimi Raikkonen for fourth at the Spanish Grand Prix.
Midway through the race, Williams told Bottas they were moving him onto "Plan C". Bottas was originally planning to do three stops but Williams changed things when they saw how well the Finn was able to manage his tyres and his pace relative to Ferrari.
Raikkonen, who was on an old set of mediums, was closing in on Bottas, who had the hard tyre, in the closing stages but was unable to get close enough to attempt a pass. Bottas admits there was very little left in the tyres when he crossed the line.
"I think the strategy team did a good job today, we actually changed the strategy," Bottas explained when asked what "Plan C" was. "Our target was to do three stops but because we saw the tyre life was OK and in the second stint our pace wasn't too much different to Kimi's, so we decided to keep going. Eventually that proved right, we just about got away with it. We knew it was going to be difficult in the end with Kimi but that allowed us to keep the position.
"I think it was a really positive race overall because we are much closer to Ferrari than any other race. The updates we brought here are small but it seems like we are definitely doing the right things."
Bottas said the memory of his battle with Raikkonen's team-mate Vettel in Bahrain, where he also held on for fourth, proved crucial in keeping his fellow countryman at bay.
"It reminded me a lot of Bahrain really, trying to keep Vettel behind. It was the same situation just a smaller period of time. I was just trying to make sure again I was getting good exits for the main straight and back straight because unlike other places it's quite difficult to overtake here. Not making mistakes was important.
"Seb was really close in Bahrain. I knew that in some places, like in the last sector in the corners, if [Raikkonen] is close there is nothing he can do. For me the main thing was to cover the main straight and the back straight and that's all what matters. You need to do some things which are maybe not optimal for the whole lap time but you need to be quick in some areas to defend."