Justin Wilson set the fastest time in the second IndyCar practice session at Milwaukee.
The Dale Coyne Racing driver, who won last weekend's race at Texas, topped the sheets with a 164.785mph (22.1744s) lap of the one-mile oval, giving him the edge over Sarah Fisher Hartman's Josef Newgarden (164.140mph).
Helio Castroneves was third fastest and best of the Chevrolet-powered drivers with his 163.927mph effort, with KV's EJ Viso and Ganassi's Graham Rahal completing the top five.
Reigning champion Will Power, who join Wilson in being one of several drivers carrying 10-place grid penalties into the weekend, was 13th fastest, while 2011 Milwaukee winner Dario Franchitti had to settle for 18th spot.