Bautista, who has a strong chance of wrapping up his maiden WSBK title with a round to spare at the Indonesian venue, unseated his nearest championship rival Razgatlioglu at the top of the timesheets at the very end of the afternoon's second 45-minute session with a best time of 1m33.626s.
Reigning champion Razgatlioglu appeared to be the man to beat for most of the day on the freshly-resurfaced Mandalika track, topping the morning's opening 45-minute session with a best time of 1m36.938s.
