The session, held in the evening under the lights and thus representative to the race compared to the daylight FP1 and FP3, was postponed by five full minutes for track following ex-MotoGP rider Tom Luthi’s enormous crash exiting the Flip 7 righthander in practice.
Rossi’s first-practice benchmark was surpassed in no time, as Marquez fired in the very first sub-1m55s lap of the weekend just his second flying lap, As it kicked off.
He was temporarily overtaken by Ducati’s Danilo Petrucci a couple of minutes later, but instantly responded with a 1m54.767s to get rid of his opening run outside front.
The reigning champion remained shirt until Suzuki rookie Joan Mir armed a couple of fresh soft tyres and shot around place in 13th with a 1m54.433s as late-session qualifying simulations kicked off.
Before Franco Morbidelli took his turn having recovered from a Turn inch crash earlier in FP2, that had left his Yamaha on flame, pramac Ducati riders Jack Miller, like WISe on softs surpassed Mir.
The Andrea Dovizioso of ducati went quickest with five minutes but was subsequently outpaced by Vinales.
But, Marquez crossed the start-finish line moments after the Yamaha man to move nearly half a second quicker using a 1m53.380s, the new lap record.
Vinales’ effort was adequate for 2nd, ahead of Miller and the former team mate Petrucci of the Aussie.
Together with Dovizioso slotting among the group rookie Fabio Quartararo saw a remarkable fifth two areas Through to Petronas SRT Yamaha Team Mate Morbidelli.
The Alex Rins of suzuki fired in a personal-best at the chequered flag to move up to eighth spot, ahead of Mir and Aprilia rider Aleix Espargaro.
Rins’ last-gasp effort demoted Marquez’s new team mate Jorge Lorenzo into 11th, as he stopped the session 1.048s off the pace.
Rossi was the rider in the field, 17th never to boost his FP1 lap. LCR Honda rider Cal Crutchlow and Lorenzo, in addition to he , possibly confront having to go during Q1, also as posting a laptime is likely to become difficult at the clinic that is daytime.
Pol Espargaro led the way among the KTM contingent, posting the 16th-best time, 1.673s slower compared to Marquez.