Rins led Yamaha rider Quartararo by 0.036 seconds, the pair turned out to be the class of the field, despite setting their best laps a few minutes before the usual late qualifying simulations.
Championship leader Marc Marquez, who was only a tenth in the top 10 of the combined training after the action on Friday, improved his lap time on Saturday morning immediately and then surpassed Quartararo’s benchmark on Friday with his next attempt.
This kept the Honda rider in the lead for the first few runs, but Quartararo soon battled his way back with a pair of fresh softs, completing the first lap under 1:40 of the weekend
On course to get even faster on his next attempt, the Frenchman was held up behind Karel Abrahams Avintia Ducati, but found himself in clear air one lap later and drove 1: 39.583 minutes.
With 10 minutes to go, Rins improved to 1: 39.547, despite driving two medium-sized tires.
He and Quartararo would hold the top two spots until the checkered flag, although neither could run better in the final minutes, with Quartararo suffering the first crash of his MotoGP career on the left-hand corner of Turn 2.
LCR Honda’s Cal Crutchlow was sitting outside of a Q2 automatic spot when the checkered flag was flying, but his final attempt proved good enough for third place, 0.164 seconds off pace.
The factory Yamaha of Valentino Rossi and Maverick Vinales completed the top 5 in front of the leading Ducati of Andrea Dovizioso.
Like Crutchlow, KTM’s Pol Espargaro secured a Q2 spot after death by running 0.310 seconds slower than Rins as he led Dovizioso’s team-mate Danilo Petrucci.
Marquez finished a low ninth, moving into Q2 alongside teammate Jorge Lorenzo, despite the pair having an enema in the final minutes of the session – with Marquez showing visible frustration with Lorenzo after seemingly put off by the triple champions on his flying champions Round.
Pramac Ducati’s Jack Miller was the last rider to go below 1:40 but was relegated to a Q1 appearance at the last moment. Next to him in the first segment will be rookie teammate Francesco Bagnaia, who was on track to make Q2 after Friday but crashed on Turn 2 on his final lap and didn’t improve his time.
Petronas Yamaha’s Franco Morbidelli was comfortably in the combined top 10 for most of the session, but suffered a heavy high side in the fast right turn at Turn 13 in the second half of FP3.
He was conscious after the impact but had to be taken to the medical center for an examination and declared fit to drive.
After the Japanese LCR driver Takaaki Nakagami was the fastest Honda on Friday, he finished twelfth in FP3 and missed an automatic Q2 place by a little more than a tenth.