Lewis Hamilton reckons rivals Ferrari was sandbagging during practice for the Spanish Grand Prix, after Mercedes led the way in both sessions.
Valtteri Bottas held a sizeable advantage in FP1, setting the best time of the day, while Hamilton laid down a benchmark in the afternoon at the Circuit de Barcelona-Catalunya.
Vettel finished as the quickest Ferrari driver on both occasions, placing third and 0.950s down in FP1, and fourth, 0.326s down, in FP2.
Hamilton, though, reckons Ferrari has yet to show its pace at the event.
“I think it’s still very close,” he said. “I’m not sure where Ferrari’s pace was today but they’re probably sand-bagging or something, they’ll bring it out tomorrow.
“The Red Bulls are obviously very close to my pace so I think it’s going to be relatively close between the top three teams.
“I can’t tell you which one is quickest at the moment because of fuelling and maybe one didn’t get their lap, or something like that, so maybe we’ll get a better understanding tomorrow.”
Expanding further on his Friday running, Hamilton said: “It was a tricky one, it was pretty windy out there, so I think every driver out there was struggling — sometimes you’ve got a tail-wind, a cross-wind, a head-wind, and so you’re constantly arriving at each corner and it’s never the same.
“So you saw a lot of drivers going off, it wasn’t that easy to stay on track. What that does is it makes it very difficult to find where the set-up needs to go.
“We’ve got some work to do overnight, I’m hoping it’s cooler and calmer tomorrow.”
Bottas was also encouraged by Mercedes’ pace but nevertheless expects another three-team battle for supremacy.
“I think it was a good day, overall,” he said.
“Especially in FP1 the car felt really good, we then did some changes for FP2 that actually didn’t improve the car, so by the end we reverted to the settings we had in FP1 and it felt OK.
“I think it was a good start of the weekend but, as always, things can really change from Friday to Saturday, we know that Ferrari is still going to be there tomorrow and Red Bull also looked good today.”