Reigning MotoGP champion Marc Marquez posted the quickest time in practice on Friday ahead of the Grand Prix of the Americas and championship leader Maverick Vinales could only manage third quickest.
Movistar Yamaha's Vinales sits top of the tree after wins in the opening two rounds of the season, capitalising on a Marquez crash to take the chequered flag in Argentina last time out.
Marquez had started that race on pole and the Repsol Honda rider appears good for pace once again after a late lap on the soft tyre saw him deliver a time of two minutes, 4.061 seconds - 0.286s quicker than the heroic efforts of Monster Yamaha Tech 3 rookie Johann Zarco.
Vinales had earlier outpaced Marquez by more than half a second in the opening session of the day, with the latter hoping to force a title tussle between the pair following a disappointing start to the campaign.
Valentino Rossi (Movistar Yamaha) - currently second in the standings behind his team-mate - was fourth fastest on Friday, 0.005s quicker than Dani Pedrosa (Repsol Honda).
FP2 saw Pull&Bear Aspar Team's Karel Abraham involved in a big crash at turn 11, leaving the Czech rider facing a trip to the medical centre.