Leclerc topped the opening 60-minute session before falling to third later in the day.
“The feeling in the car was good,” Leclerc said after Friday's running.
“We still haven't found the sweet spot in terms of balance, but we tried many different things throughout the day and know which direction we want to go in.
“Our race pace looked stronger than our qualifying pace, so if we put it all together there is quite good potential to have a solid weekend.”
Across the garage, his team-mate's weekend is already compromised. Sainz is one of six drivers who will take penalties ahead of Sunday's race.
The Spaniard will start from the back of the grid after Ferrari fitted a new energy story, MGU-K, gearbox, and control electronics to his car.
He enjoyed strong single-lap pace throughout Friday but with qualifying of limited value his focus is instead on long run pace.
“Overall it has been a positive day,” said Sainz.
“We still need to check all the data, but I felt quite comfortable in the car and the package this weekend seems to be working well.
“There is still work to do to try and improve the pace on the long runs, so we'll look into every detail tonight and try to improve for tomorrow but especially for the race.”
While Sainz will drop to the rear, Verstappen is set to only fall five places after he received a (fifth) internal combustion engine.
A final hour of practice remains to refine car set-up on Saturday afternoon from 13:00 local time.
That feeds into qualifying three hours later, that session starting at 16:00 CEST (10:00 ET/00:00 AEST).