The Ferrari driver's best time of one minute 16.231 seconds was close to the 2018 Spanish Grand Prix pole time by Lewis Hamilton for Mercedes.
Ferrari's Charles Leclerc recorded the fastest lap in Formula One's pre-season testing to top the lunchtime timesheets at the Circuit de Catalunya on Thursday.
The young Monegasque's best time of one minute 16.231 seconds on a sunny morning with ambient temperatures of 21 degrees celsius was set on the softest, and fastest, C5 compound tyres.
The lap was close to the 2018 Spanish Grand Prix pole time of 1:16.173 set by Lewis Hamilton for Mercedes, and came as a boost for Ferrari after Sebastian Vettel had crashed on Wednesday.
Hamilton's team mate Valtteri Bottas reiterated the view he expressed last week that Ferrari are still ahead of both Mercedes and Red Bull.
"The whole field looks like it's a bit tighter than last year or the year before, but it's only guessing," added the Finn. "You never know what people bring to Melbourne."
The season-opening race in Australia is on March 17.
Anglo-Thai driver Alexander Albon of Toro Rosso was second fastest on the penultimate day with a lap of 1:16.882, also on C5 tyres, with McLaren's Lando Norris third in 1:16.882.
But Norris's team mate Carlos Sainz, who went quickest on Wednesday, played down the times.
"This is just testing and we are just doing more qualifying-based runs so we can see what you can do with the car. I guess we need to wait and see what the others can do on those runs," said the Spaniard.
Hamilton, who will be chasing a sixth title this year with Mercedes going for a sixth successive championship double, did more laps than anyone before lunch (85) but was eighth fastest on the hard C2 tyre as he focused mainly on long runs.
Leclerc did 54 laps, Norris 66 and Albon 75.
