Danilo Petrucci obliterated the Sepang lap record to end the first MotoGP pre-season test fastest of all, leading an all-Ducati top four, with Pramac rookie Francesco Bagnaia just 0.063 seconds behind him.
A frantic opening hour resulted in a constant change at the top of the timesheets, with Petrucci setting a benchmark that would not be beaten 45 minutes in with a 1:58.239s.
Yamaha's Valentino Rossi set the early pace during the frenetic first hour of action with a 1:59.155s, before Franco Morbidelli on the Sepang Racing M1 edged ahead by a tenth to take over top spot.
The Italian duo soon found themselves usurped by Thursday pacesetter Maverick Vinales, who was the first to set a new unofficial lap record with a 1:58.644s.
Around 10 minutes later, Petrucci guided his GP19 to a scorching 1:58.239s, with Ducati stablemate Francesco Bagnaia moving his Pramac GP18 – now fitted with last year's aerodynamic package – 0.063s adrift in second.
Petrucci and team-mate Andrea Dovizioso debuted Ducati's new aero fairing – which was not meant to break cover until the Qatar test – while the works Yamaha duo also had a new aero package to run.
By midday, six riders had dipped underneath the unofficial lap record of 1:58.8s set by then-Ducati man Jorge Lorenzo, with times at the sharp end of the field remaining unchanged through to the chequered flag.
Petrucci did not spend long on the new fairing, as he crashed at Turn 5. Having completed his testing program, Ducati decided to end his day early.
Bagnaia held onto second ahead of Pramac team-mate Jack Miller, who suffered another fall late in the session, with Dovizioso a further 0.172s behind in fourth.
Vinales was one of several riders to focus on race simulations on Friday, and was fifth on the first of the Yamahas from LCR's Cal Crutchlow – who crashed early in the day at Turn 2 – and Aprilia's Aleix Espargaro.
Morbidelli remained ahead of Rossi, with the sister LCR bike of Takaaki Nakagami splitting the duo, while Marc Marquez once again limited his running to just 39 laps in 11th on the works Honda.
Alex Rins led the Suzuki charge in 12th, 0.010s behind Marquez, with Honda test rider Stefan Bradl, Avintia's Tito Rabat and Rins' team-mate Joan Mir rounding out the top 15.
Aprilia's Andrea Iannone was absent from the final day of running, as he continued to battle a dental infection. Test rider Bradley Smith [26th] rode in his place on Friday.
