Misano Adriatico, Italy: Maverick Vinales, in the opening practice session on a dry Misano track, and Johann Zarco, in the rain on the second, dominated warm-ups for the San Marino Grand Prix in Misano.
Championship leader Fabio Quartararo (Yamaha) finished seventh in the combined times after struggling with the tough conditions of the second free practice.
Vinales (Aprilia) clocked the best time of 1min 32.666sec to finish ahead of compatriot Joan Mir, on a Suzuki, with the Ducatis of Francesco Bagnaia and Jack Miller following.
Zarco, also on a Ducati, was 11th in the combined times, but had topped times in the second session and will no doubt be hoping for more rain come the weekend after mastering the wet conditions.
Home favourite Valentino Rossi, soon to be retired, could only manage 19th.
Saturday will see the riders have two more practice sessions before qualification at 1210 GMT.
Leading combined times after two practice sessions
1. Maverick Vinales (ESP/Aprilia Racing Team Gresini) 1min 32.666sec, 2. Joan Mir (ESP/Team Suzuki Ecstar) + 0.080sec, 3. Francesco Bagnaia (ITA/Ducati Lenovo Team) 0.135, 4. Jack Miller (AUS/Ducati Lenovo Team) 0.193, 5. Alex Rins (ESP/Team Suzuki Ecstar) 0.219, 6. Pol Espargaro (ESP/Repsol Honda Team) 0.353, 7. Fabio Quartararo (FRA/Monster Energy Yamaha MotoGP) 0.358, 8. Stefan Bradl (GER/Repsol Honda Team) 0.381, 9. Marc Marquez (ESP/Repsol Honda Team) 0.434, 10. Aleix Espargaro (ESP/Aprilia Racing Team Gresini) 0.436