Rubens Barrichello said he suspected something might have broken on his car after being beaten to Spanish Grand Prix victory by his Brawn teammate Jenson Button.
The Brazilian had led the first half of the race, but when Button switched from a three to a two-stop strategy, Barrichello was unable to pull out enough of a margin to stay ahead once he had made his additional stop.
"The race evolved quite well, I had a great start and went to the lead," said Barrichello. "I was running a tiny bit quicker than Jenson to begin with and had two more laps of fuel, so it was running quite well. I heard they changed Jenson's strategy and I had to keep on pushing.
"My third set of tires was not good, I don't know if something was broken on car. So I couldn't keep the pace up, and from then on it was a struggle to keep the car on the track and a relief to come second.
"I'm disappointed because I didn't win the race because I felt I had it in the bag today, but it's still great for the team."
He admitted that he had not expected the team to change Button's strategy at the first stops.
"I was a lap or two longer, and Jenson caught me up a little bit on the strategy because of the safety car, so I was quite happy because having a lap longer and being in front I was delighted, I had the race in my hands," said Barrichello.
"So I was actually quite surprised when they switched Jenson to two, but from then on I just had to go flat-out."
Barrichello added that he had pitted early at the end of the race due to traffic, even though by that time Button had switched to the unfavored hard tires and was losing time to him.
"I came in a lap or two earlier for my final pit stop because there were lots of cars and blue flags and I was losing time," said Barrichello.