Max Biaggi moved to the top of the timesheets in second qualifying at Miller Mototsports Park as Aprilia unleashed a fearsome pace around the United States circuit.
The Italian recorded the fastest lap of the weekend so far with a 1min 48.115secs effort, but it was Biaggi's advantage down the lengthy home straight that drew the most attention.
Topping out at 309kph, Biaggi was several kph faster than his rivals in a straight line, although his Aprilia Alitalia team-mate Leon Camier did achieve 311kph before crashing in the final minutes.
Overnight leader Jakub Smrz was second fastest, ahead of BMW's Troy Corser, while Althea Racing's Carlos Checa and Shane Byrne made it a strong session for the privateer Ducati contingent in fourth and fifth, ahead of factory rider Michel Fabrizio.
Yamaha's Cal Crutchlow, the only rider to get close to Aprilia's top speed, was seventh best, ahead of Leon Haslam – who failed to improve his Q1 time -, Camier and James Toseland.
Further back, just one rider will not re-appear again in Superpole later this afternoon, that being Matteo Baiocco, which means his Pedercini Kawasaki team-mate makes it through the grid-deciding session for the very first time.