McLaren's Lewis Hamilton and Ferrari team manager Massimo Rivola reckon that some teams might be able to stop only once for tyres in the Canadian Grand Prix.
Hamilton was quickest on Friday in Montreal, and felt the tyres held up well over long runs.
"Tyre degradation could be an issue, and it will be very close, Ferrari seem to have to have good tyre degradation at the back end of their car, at least in the last race, so it looks like it could be another one-stop race, with the tyres doing well over 30 laps," Hamilton said.
Rivola agreed with Hamilton's assessment.
"I think it will be one of the key points of the race," he said. "I don't know how many of us were convinced Monaco would be a one-stopper. Today we've seen very long runs from whoever has used the super softs more than us.
"We've seen [Sebastian] Vettel doing 19 laps on super softs while remaining very consistent. We've seen both Lotuses in FP1 doing 21 very consistent laps.
"On paper it's true it may seem like a one-stop race, but Sunday's temperatures will be very different from today's. With probably 15 degrees more in asphalt temperatures it might be a completely different scenario, so we'll need to be ready to react depending how it presents itself."
Hamilton added that the super soft compound lasted longer than expected but that it did not give the one-lap performance advantage that has been seen for most of 2012.
"I preferred the prime to be honest even though the soft did go a bit quicker. It wasn't as big as it normally is, it is normally quite a big gap but I think it is only three or four tenths difference," he said.