Ferrari enjoyed a promising start to Formula 1 pre-season testing with Charles Leclerc spending much of the day as the fastest runner.

The Monegasque driver was the quickest of the morning’s 10 runners, his time standing until the final hour when Lando Norris bested it.

Carlos Sainz also proved rapid in the F1-75, posting a time only marginally slower than Leclerc’s to leave the Scuderia one-two on the timesheets for a period.

They ultimately ended the day second and third behind Norris but with the most running of any team on the grid (153 laps/715.275km).

“The initial feeling is not bad, but we shouldn’t get carried away by the timesheets today, as these are early days and everyone is still hiding their true form,” warned Leclerc.

“It’s impossible to have a clear picture just yet, so we have to stay focused and keep working hard.

“We put in a lot of laps, more than any other team today, and that’s a positive we will build on.”

Ferrari completed a ‘demonstration’ run last week, limited to 15km, and yesterday was on track in Barcelona for a ‘filming day’.

Wednesday marked the first real opportunity for the drivers to get to grips with their new machine.

“Today was the first time I was in the car with a proper run plan, unlike the previous times when we basically did shakedowns,” said Sainz.

“We could finally push a bit and start learning from these cars.

“The timesheet is unimportant at this early stage, but it was very positive to put in a good number of laps and get a real feel at the wheel.

“We still have a lot of work to do but today we could already start feeling some differences from last year, although in terms of getting used to it I don’t feel it’s going to take too long.

“For sure the last tenths will be tricky to find, but that is the interesting part! Anyway, that’s not the aim here in Barcelona as we still have more testing ahead of the first race.

“A good first day and I’m looking forward to tomorrow.”

Sainz and Leclerc will again share the running on Thursday, the Spaniard set to start the day before handing the car over for the afternoon session.

Running in Barcelona begins at 09:00 local time (19:00 AEDT).