Fabio Quartararo showed impressive pace in practice for the Catalunya Grand Prix and sits top of the timesheets ahead of FP3 and qualifying.
The French rookie, who underwent arm pump surgery before being passed fit to race this week, has consistently produced strong times over a single lap this season, including registering pole at the Spanish Grand Prix.
And he again showed that speed on his Petronas Yamaha in Friday's two sessions, finishing second in FP1 before topping the FP2 standings.
Reigning champion Marc Marquez, who leads the riders' standings, was fastest in the first session by 0.111 seconds over Quartararo ahead of his home race, before he was 17th in the next. He sits ninth overall as things stand ahead of Saturday's action.
Quartararo took the honours in that second session – which was comfortably the faster of the two – recording a time 0.281secs quicker than Ducati's Andrea Dovizioso.
Dovizioso, trailing Marquez by 12 points in the championship, had a good day, his second place in FP2 following up a fourth-place finish in the opener.
Takaaki Nakagami sits third overall, making him the top Honda on track, just ahead of Red Bull KTM Factory Racing's Pol Espargaro.
Jorge Lorenzo, showing some modifications to his brake cover after making a trip to Japan to Repsol Honda's team headquarters since the last race, was just 17th and 13th respectively, leaving him in the mix for Q1 as things stand.
Danilo Petrucci, the winner at Mugello, is eighth overall, one place behind Valentino Rossi. But Alex Rins has work to do ahead of his home race, as he sits 11th after going off the track in FP2.