Renault was surprised that it suffered high tyre wear in the Canadian Grand Prix despite Robert Kubica starting on the harder medium tyres.
The Pole had hoped that his tyre strategy would give him the edge over the drivers around him who were using super softs for the first stint, but he was affected by severe degradation as well, and could not stay with the leaders - eventually finishing seventh.
"The six points I got this afternoon were my toughest points of the year," he said.
"We chose to qualify on the prime tyre yesterday and hoped it would be an advantage in the first part of the race, but unfortunately it didn't work out. I had a lot of rear degradation in the first stint, which meant I pitted early, then the rear tyres went off in the second stint as well."
Renault's chief race engineer Alan Permane agreed that the high tyre wear had come as a surprise.
"This afternoon's race was all about tyre degradation," he said. "We had hoped that our decision to qualify on the prime tyre with Robert would pay off, but we saw more degradation than expected in the first two stints, and that ultimately cost him position to [Nico] Rosberg - even though we ran in front of him for much of the race."
Kubica's battling race was also enlivened by a physical dice with Michael Schumacher that saw both take to the grass, and a close call with Adrian Sutil as he dived into the pits across the front of the Force India.
"I was racing him on my in-lap and we were side by side before the last corner, I was on the right, so I backed off and pulled behind him to take my line for the pits, but he braked very early and hard," said Kubica. "I had to go round him to avoid causing an accident."