Montreal - Sebastian Vettel revealed on Sunday that he was concerned about the dangers of a possible track invasion when the chequered flag was waved prematurely before he won the Canadian Grand Prix.

The flag was waved by model Winnie Harlow who said she was just "following instructions", but it meant the result of the race was decided by the positions at the end of lap 68 instead of lap 70.

Vettel said he realised what had happened on the penultimate lap and sent a radio message to try and help avoid confusion.

"Fortunately, we had radio and we had the lap counter in the car and my pit board was accurate," said the four-time world champion Ferrari driver.

"But if you lose radio and maybe the pit board is not there, then you back off and being in the lead, you hope all the others back off as well.

"I was just worried. I told them on the last lap, so people don't jump on the track, waving flags and celebrating, because we are still going at full pace.

"I even watched it on the TV, on a trackside screen, and after I saw the flag it said 'final lap' on the graphics so then I was a bit confused.

"I told them the race isn't over yet and they said 'no, keep pushing' and I saw some of the marshals were celebrating. They peaked a bit early!"

Frenchman Pierre Gasly of Toro Rosso, who finished 11th, said the flag’s early appearance was "risky".

He added: "I think it is the first time I have taken the chequered flag two times at the same race!"