Mercedes was expecting Ferrari to put up more of a fight in qualifying for the Canadian Grand Prix on the back of its power unit upgrade this weekend.
Mercedes' analysis of Friday practice estimated the Ferrari would be 0.2s off its own cars, but in qualifying Lewis Hamilton was 0.6s ahead of Kimi Raikkonen in third.
"I think we anticipated they would be a couple of tenths off," Hamilton said. "Although we weren't really focusing on them, we were focusing on ourselves, to see them further than that is a positive."
Mercedes boss Toto Wolff had put Ferrari's improved Friday pace down to the power unit, but admitted the data had been difficult to analyse.
"The Ferrari running on Friday looked different. It was either different because what they have done with the power unit is new or they were playing around with fuel loads. It didn't quite add up, so I can't really tell you what we are expecting for tomorrow.
"On the first look it was very impressive and then if you compared the data properly and looked at corner speeds and the speeds on the straight, which were really impressive, we found that we still had a bit of a margin, even on the long runs, of a couple of tenths. But I wouldn't want to say that is true for sure, because it is more difficult to analyse than previously."
Wolff said the true pace of the Ferrari may also have been masked by Sebastian Vettel's MGU-H problem that prevented him from setting a representative time in qualifying.
"A bit surprised, because on the Friday it looked like a massive step ahead and the pace was impressive and what we saw on the GPS data was impressive. Somehow it did not materialise today. We haven't seen Sebastian properly competing, so maybe it's too early to say it didn't really work out. We need to wait for tomorrow I guess."