Narain Karthikeyan has reacted angrily to Felipe Massa's claim that he was responsible for the Ferrari driver missing out on a podium at the Canadian Grand Prix.

"The blame game starts when your seat is under threat," Karthikeyan told ESPNF1, making a reference to persistent rumours that Massa could be replaced.

Following the eventful Canadian Grand Prix on Sunday, Massa, who finished sixth, blamed Karthikeyan for causing an accident that dropped him from third to 12th.

"My chances of finishing on the podium and also of fighting for the win just evaporated when I was passing Karthikeyan," he said. "He was going very slowly on the dry line but then, as I was passing him on the wet, he accelerated and I lost control of the car ending up in the wall. I am angry, there is no point denying it."

But Karthikeyan does not agree with Massa's version of events: "I didn't slow down at all. He came really fast behind me. He then changed his racing line, went on the wet part and spun."

Although Karthikeyan enjoyed his best race since his comeback, a post-race penalty for skipping the final chicane saw him demoted from 14th to 17th and admitted, "I was disappointed with the stewards' decision."

The Indian added that he had been taken by surprise when his team fitted slick tyres at the final pit stop rather than intermediates.

"I didn't expect to be called in after having passed Tonio [Liuzzi] with the intermediates," he said. "I wanted to stay out on the same set for a bit longer. However, for whatever reason, the team called me in, put on slicks [without informing me about the change from intermediates to slicks] and from there, I dropped quite a few places.

"I did everything right in the race and managed to overtake Virgin cars as well as Tonio."