Andrea Dovizioso held onto top spot at the end of a frantic second MotoGP session in Qatar, 0.006 seconds ahead of Ducati stablemate Danilo Petrucci.
On his first flying lap, Marc Marquez shot to the top of the standings with a 1:55.410s to go three tenths quicker than his FP1 best, while Yamaha's Maverick Vinales – who spent the entirety of the afternoon session on the same set of tyres – was his closest challenger on a 1:55.792s.
Marquez found himself deposed by factory-backed LCR rider Cal Crutchlow, though the Briton's 1:55.306s only kept him top of the pile for a couple of minutes as the reigning world champion took over again with a 1:55.043s.
The Honda rider's time stood as the benchmark up until the final 11 minutes, when Alex Rins, fitted with fresh soft slicks, guided his Suzuki to a 1:54.997s.
A flurry of fast laps followed, with Pramac's Petrucci storming to the top of the times with a 1:54.367s with three minutes to go, before Dovizioso edged ahead on a 1:54.361s.
Rins found himself shuffled back to ninth as he began his final lap, but leapt up to third at the chequered flag, ahead of Jorge Lorenzo.
Lorenzo's session got off to a troubled start, as he was forced to swap bikes when his first machine began sparking due to its chain rubbing against some bodywork. Once again running without the aerodynamic fairing, the Spaniard was almost half a second down on his team-mate.
Andrea Iannone lifted himself into the top five at the end, the Suzuki man bumping Marquez down to sixth, while Dani Pedrosa split his teammate and Crutchlow.
Valentino Rossi headed Johann Zarco to complete the top 10, which could well be crucial in securing a place inside qualifying two, as third practice will be run in hotter conditions on Saturday.
Vinales found himself outside of the top 10 in 11th, while Aprilia's Aleix Espargaro will also need to improve in FP3 to capture an automatic Q2 spot.
Tito Rabat edged ahead of fellow GP17 runner and former team-mate Jack Miller, with Takaaki Nakagami ending the night as top rookie rider in 15th.