Jorge Martin sealed a Friday practice double to put down a marker on the opening day of the Thai MotoGP round despite crashing out at the end of afternoon practice.
The Pramac Ducati rider, also fastest in FP1, led Aprilia Racing’s Maverick Viñales and Aleix Espargaro, with the top three separated by only 0.160s at the Buriram International Circuit.
Championship leader Francesco Bagnaia was seventh as the Italian sealed his passage to Qualifying 2 after missing the cut in the previous two rounds.
Frenchman Johann Zarco made a big step forward from the morning with the Australian Grand Prix winner slotting into fourth ahead of VR46 Ducati’s Luca Marini and Marco Bezzecchi.
Repsol Honda’s Marc Marquez will have to go through Qualifying 1 on Saturday, narrowly missing out as he finished 11th, 0.369s down on Martin.
Defending champion Bagnaia returned to pit lane shortly after the session began due to an issue with his Desmosedici.
Yamaha’s Fabio Quartararo was the early pacesetter from Fabio Di Giannantonio (Gresini Ducati) before team-mate Alex Marquez lapped in 1:30.728s to go top.
Viñales posted a 1:30.613s to regain the lead on the timesheets from Marquez by 0.115s at the halfway point in the hour-long session, with Red Bull KTM’s Brad Binder only four thousandths of a second adrift in third.
Quartararo, Raul Fernandez (RNF Aprilia) and Di Giannantonio were the top six, separated by three tenths, with Martin in seventh and Bagnaia 12th.
Honda’s Marquez had a scare when he was hit by a piece of a broken fairing on his right shoulder from Martin’s Ducati, although the Spanish rider escaped unscathed.
Di Giannantonio jumped to second inside the last 25 minutes, 0.091s adrift of Viñales, while Binder improved to a 1:30.246s, just 0.007s up on Viñales.
Bezzecchi briefly moved third as a flurry of time attacks began in the stifling heat in Buriram.
Viñales reclaimed the advantage with a hot lap in 1:29.924s with Bezzecchi now second and Zarco improving on the Pramac Ducati to go third with 10 minutes left. Martin was fifth with Bagnaia 11th and outside the Q2 spots at this point.
Bagnaia then hauled himself into sixth on the factory Ducati with seven minutes to go, 0.252s off Viñales.
The final time attacks got underway with five minutes remaining and it was Martin who went fastest in 1:29.826s.
The Spaniard then crashed out at Turn 3 on his next lap as he tucked the front of his Ducati in the first spill of the weekend. Martin, though, remained on top as the seconds ticked down.
A raft of laps in the closing stages were cancelled due to a yellow flag in Sector 2, including a time for Binder that would have moved the South African into second.
That left Martin in the number one spot by 0.098s from Viñales, with Espargaro third ahead of Zarco, Marini and Bezzecchi.
Bagnaia was next in seventh, with Quartararo, Binder and Augusto Fernandez (GasGas Tech3 KTM) the top 10.
Along with Honda’s Marquez, Franco Morbidelli (Monster Energy Yamaha), Jack Miller (Red Bull KTM), Di Giannantonio and Gresini team-mate Alex Marquez will have to participate in Qualifying 1.
