Spaniard Jorge Martin set the fastest time as Ducatis had another strong day Friday in practice for the Grand Prix of the Americas.
Martin on a Ducati Pramac recorded a time of 2 minutes 2.178 seconds in the second session of the day to edge reigning champion Francesco Bagnaia, on a factory Ducati, by 0.063sec.
In the injury absence of Honda leader Marc Marquez, who has claimed six of the eight times the race has been run at the Circuit of The Americas, and Enea Bastianini, who was first last year, Alex Rins, is the only previous winner in the field.
The Spaniard, who won in the elite class in Austin in 2019, was the only non-Ducati in the top five, finishing third on his LCR Honda.
Luca Marini, who has been fastest in the morning session on 2:03.25 improved by more than an eighth of a second in the afternoon and was fourth on his Mooney Ducati.
Alex Marquez was fifth on his Gresini Ducati.
The pressure was on under the new format. The ten fastest in Friday's practice advance directly to the 12-rider Q2 second qualifying session on Saturday which establishes the first four rows for the grid in the day's sprint race.
Championship leader Marco Bezzecchi was 11th on his Mooney Ducati 0.7sec behind Martin and will have to go through Q1.
Johann Zarco, who is third in the standings, finished 14th fastest after crashing his Ducati-Pramac in the second session. He escaped unscathed.
Stefan Bradl, standing in for Marc Marquez also crashed.
Miguel Oliveira, who was taken down by Marquez in the opening race of the season and missed the Argentina Grand Prix, crashed twice.