Sebastian Vettel says the threat of rain meant he had to go 'flat out' with his upgraded Ferrari during free practice for the Canadian Grand Prix, with the German encouraged by the early feedback.

Fifth quickest in the morning - 1.5secs adrift of the leading Lewis Hamilton -, Vettel progressed to second best and just three tenths behind the Mercedes driver in the weather-hampered FP2, notching up particularly encouraging pace on the longer runs.

Indeed, the former champion was satisfied with the form of the Ferrari with its upgraded engine, adding that he is certain there are still improvements to be made ahead of qualifying.

"There was no easing in, we went flat out straight away," he said. "Obviously time is very valuable and you try to get as much information as soon as possible and I think everything seemed to be working as expected

"In the morning we tried to prepare for the race. Lap times don't really matter so much on this day, it's all about the feeling you've got in the car.

"I haven't seen much yet of the others but I think it felt OK and now we have to see where we are. I think we can still improve. I am not entirely happy with the runs I had but I don't think anybody was with the short amount of time we had today."