Jorge Martin missed another chance to slash Pecco Bagnaia's championship lead as a failed tyre gamble meant he fell from first to fifth on the Australian Grand Prix's last lap and his Pramac Ducati team-mate Johann Zarco finally got a first MotoGP victory.
Bagnaia's points gap was on course to drop back to just four at one point when he was shuffled down to fifth while Martin dominated.
But instead Bagnaia was able to increase his cushion to 27 points as he slipped through to second when Zarco overtook the fading Martin for the lead on the final lap.
The grand prix and sprint have swapped places on the schedule this weekend to make sure the main race could take place given the extreme weather forecast for Sunday.
Dominant pole-winner Martin was one of just a handful of riders to pick the soft rear tyre and he used it to make an early break, building a lead that peaked at three and a half seconds.
Bagnaia came under initial attack from fast-starting home favourite Jack Miller, then was overtaken for third by Fabio di Giannantonio's Gresini Ducati and later by Zarco too.
Brad Binder spent much of the race in a clear second between Martin and di Giannantonio, but that pack closed together into the final 10 laps, as di Giannantonio overtook the KTM and brought Zarco and Bagnaia with him too.
The increasingly close fight for second between that quartet looked like it might save Martin as his pace began to fade.
Zarco got to the front in the queue in a move on Binder that sent the KTM down to fifth, potentially giving Martin his team-mate to protect him.
But as they went onto the final lap, Martin's pace had become so poor that Zarco had no choice but to try to overtake.
As he did so, Bagnaia pounced too and grabbed third, with Martin slipping back behind first-time podium finisher di Giannantonio and Binder too to fifth.
Zarco resisted Bagnaia to win by 0.201s, finally taking his first MotoGP win in his seventh season and four events before he leaves the Ducati fold for LCR Honda.
Marc Marquez gave more evidence of the soft tyre’s fragility by going from leading the pack pushing Bagnaia for fourth early on to only just getting a point in 15th.
Marco Bezzecchi had a strong end to the race to progress to sixth for VR46 Ducati ahead of Miller.
It was a muted race for Aprilia. Aleix Espargaro and Maverick Vinales both lost ground on lap one and ended up eighth and 11th, with Alex Marquez and Enea Bastianini between them.
Yamaha had an abysmal day. Fabio Quartararo at least edged up to 14th by the flag, after he and team-mate Franco Morbidelli had initially run around at the back with just Taka Nakagami behind them.
Marquez was still top Honda in 15th as Alex Rins withdrew before qualifying with new pain from his leg injury and Joan Mir yet again crashed out, this time while dicing with Luca Marini.
A further schedule change has been made for Sunday to try to get racing in before the worst of the weather hits, with everything moved forward by one hour. That means the sprint is scheduled to run at 1pm local time, after Moto3 and Moto2's races.
|Pos||Name||Car||Laps||Laps Led||Total Time||Fastest Lap||Pitstops||Pts|
|3||Fabio Di Giannantonio||Ducati||27||0||+0.477s||1m29.218s||0||16|