Washington - Four-time defending Moto Grand Prix of the Americas champion Marc Marquez captured his fifth consecutive event pole in dramatic style on Saturday, edging series leader Maverick Vinales on his final qualifying lap.
Honda rider Marquez saved the best for last to complete the fast lap in 2:02.741 to edge his Spanish compatriot, a Yamaha rider who won this season's two opening races at Qatar and Argentina, by 0.130 of a second.
Vinales's team-mate, Italy's Valentino Rossi, completed the front row in another late charge for third in 2:03.673.
The front-row fight sets the stage for a showdown of the Spaniards in Sunday's race over a 20-turn layout where Marquez has swept every GP race contested but Vinales has swept the 2017 start, winning two weeks ago in South America after Marquez crashed out early.
Spain's Dani Pedrosa, a Honda rider who has twice made trips to the Americas podium, was fourth and will be joined on the second row by French rookie Johann Zarco (Yamaha) and Spain's former world champion Jorge Lorenzo (Ducati).
Spain's Aron Canet smashed the Moto3 one-lap circuit record by seven-tenths of a second to grab his second career pole in 2:14.644.
The Honda rider, seeking his first victory, beat Spanish series points leader Joan Mir, winner of the season's first two races riding a Honda, by 0.987 of a second with defending race champion Romano Fenati of Italy, also on Honda, in third, another 0.01 adrift.