Dani Pedrosa ended Friday's MotoGP running ahead of the Czech Grand Prix fastest of all after topping FP2, while Honda teammate Marc Marquez was 10th.
Jorge Lorenzo was one of only a handful of riders to start the session on the soft front and rear combination, and used the added grip from his rubber to set the early benchmark at 1:57.486s.
Suzuki's Alex Rins usurped the Ducati man soon after, though, with a 1:47.456s, before Marquez leaped up to top spot with a 1:57.213s.
Marquez continued to wipe time off of his benchmark with a 1:57.084s, which he duly improved to a 1:56.635s, while Honda teammate Dani Pedrosa closed to within 0.143 seconds in second.
Andrea Dovizioso was the first mover on fresh hard rubber in the closing stages, the Ducati rider usurping the Honda pairing with a 1:56.389s.
Pedrosa, running a new soft rear tyre, demoted former teammate Dovizioso to second with a 1:56.089s, which he improved to a 1:55.976s to see out the session fastest of all.
Pramac's Danilo Petrucci, who debuted a new aerodynamic update on his factory GP18 midway through the session, leaped up to second at the end with a 1:56.099s, while Ducati stablemate Alvaro Bautista completed the top three.
Tech3's Hafizh Syahrin was fourth fastest and top Yamaha in FP2, just over three tenths from top spot aboard his year-old M1, while Dovizioso slid to fifth at the chequered flag.
Maverick Vinales improved markedly on his 14th-place finish n FP1 to end the day sixth overall ahead of Yamaha teammate Valentino Rossi, while Tito Rabat leaped up into the top 10 in eighth late on.
FP1 pacesetter Johann Zarco was sixth tenths from Pedrosa's best in ninth on a 1:56.535s, a tenth quicker than Marquez, who once again opted against switching from the tyres he started the session on for a late time attack.
Despite leading the session in the opening minutes, Ducati's Lorenzo found himself down in 15th, two tenths behind LCR Honda's Cal Crutchlow.
Stefan Bradl ended Friday 18th on his HRC-liveried RC213V, while fellow wildcard Sylvain Guintoli was last of the 26 runners on his Suzuki.
