Cal Crutchlow was quickest at the end of the opening practice session ahead of this weekend's FIM Supersport World Championship round at Miller Motorsport Park.
The championship leader put up a time of one minute 53.790 seconds on the Yamaha to finish less than a tenth quicker than Provec Motocard Kawasaki's Joan Lascorz.
Kenan Sofuoglu, who sits third in the riders' standings, 36 points behind Crutchlow, was third for HANNspree Ten Kate with a time of 1min 54.158secs.
Crutchlow's nearest title rival, Parkalgar Honda's Eugene Laverty, was fourth on Friday, over four tenths off the pace of the Briton.
Fabien Foret (Yamaha) and Andrew Pitt (HANNspree Ten Kate Honda) completed the top six.