Earlier, Brad Binder from Krugersdorp took his second consecutive Moto3 win by less than a tenth of a second after a race-long battle with Romanto Fenati to extend his championship lead to 24 points.
Lorenzo made a perfect start as Marquez wheelied off the line, to lead through the first chicane with Ducati Team rider Andrea Dovizioso behind him - but Marquez was soon up to fourth as he charged past Pol Espargaro (Yamaha Tech 3). Rossi tried attempted to follow him through but found himself swamped by the likes of Aleix Espargaro (Suzuki) and Bradley Smith (Yamaha Tech 3).
As they crossed the finish line for the first time Lorenzo's lead stood at half a second from Dovizioso and Iannone behind. It was not the start Rossi had wanted, up just a single place from seventh on the grid as the second lap began.
Lap four saw Rossi improve his pace, going half a second quicker than Marquez who was just ahead. The pair weren’t the only ones closing up, Iannone also making significant progress on his team-mate – only to crash at Turn 8 on lap seven, followed soon after by Honda privateer Cal Crutchlow, in his fourth race crash of the year.
Lap 13 saw Rossi slip past Marc Marquez, making it a three-way battle for second as Lorenzo continued to run away at the front. Just a few corners later Rossi was up into second and matching Lorenzo’s times. A thrilling battle for second was brewing until Dovizioso and Marquez went down in perfect synchronisation (without touching each other!) in Turn 7 on lap 16.
That put Suzuki’s Maverick Vinales in line for his first MotoGP podium and Lorenzo on the cusp of taking the championship lead – but the falls continued and soon Marquez was up to 13th, despite missing a large section of his side fairing.
Lorenzo, 7.8 seconds clear with five laps to go, was having no such issues as he calmly ran his own race. With gaps of at least three seconds splitting the top three, each eased their pace to guarantee a finish in the clearly difficult conditions.
Marquez’ factory Honda team-mate Dani Pedrosa was unable to close the gap to Vinales despite his best efforts and had to settle for fourth ahead of Pol Espargaro, once again the fastest privateer, in a credible fifth, one spot ahead his brother Aleix on the second works Suzuki.
Ducati privateers Danilo Petrucci and Hector Barbera, followed by Aprilia riders Alvaro Bautista and Stefan Bradl completed the top 10. Only 13 riders out of 21 starters finished, with the defending champion in the unusual position of coming in stone last.
The win saw Lorenzo move past Marquez to the top of the championship, with Rossi still third, 12 points behind Lorenzo after each of the top three had crashed out once in the first five races of the 18 race calendar.
Polesitter Thomas Luthi made a great start in a race where only six of 28 starters were not Kalex-mounted, with Franco Morbidelli shooting into second from fifth on the grid, as championship leader Sam Lowes and Johann Zarco were pushed down the order in the opening corners.
As the field came through Turn 6 for the second time, Jonas Folger suffered his second race crash of the year. He was unhurt, but his championship hopes took a significant blow.
Luthi worked hard to break away from his pursuers but Alex Rins stayed right with him and briefly grabbed the lead on lap five. Three Italians chased them, with Speed Up rider Simone Corsi hanging on to third as Franco Morbidelli and Lorenzo Baldassarri disputed fourth.
Rins and Luthi continued to swap positions on almost every lap until the shift light on Luthi’s Kalex stopped working properly on lap seven, making it very difficult for him to judge his gear-changes, and he began to drop back.
Corsi and Baldassarri quickly passed the Swiss rider, but Lowes was also unable to match the pace of the leaders, running a lonely seventh for much of the race.
Corsi made sure Rins was unable to break away, working his Speed Up hard and keeping the gap consistently less than half a second, while Luthi worked out how to ride around the faulty shift light and got back on the pace, re-passing Baldassarri for third on lap 17.
Then reigning title-holder Jonann Zarco’s home race went from damage control to disaster as he crashed out at Turn 14 on lap 18. He remounted down in 24th, where he finished.
Luthi’s third place then became a certainty as Baldassarri fell at Turn 3, getting back on his Kalex after the spill but outside the points.
Three laps from the end Rins was able to get away from Corsi, coming home 1.8 seconds clear with Corsi and Luthi joining him on the podium.
Morbidelli managed an important fourth place ahead of a late-charging Takaaki Nakagami, with Lowes, Axel Pons, Hafizh Syahrin, Luis Salom and Miguel Oliveira rounded out the top 10.
Niccolo Antonelli (Honda) got a perfect start from pole as the field swept through the fast Turn 1, with Khairul Idham Pawi (Honda) pulling a great run off the line to slide in behind Binder’s works KTM.
Binder moved to the front on a five-way battle for the lead at the start of lap 2, only for KTM privateer Romano Fenati to grab the advantage at the Dunlop chicane, setting up a race-long duel between the two.
Rookie Aron Canet (Honda) was a man on a mission, getting ahead of team-mate Jorge Navarro on lap 12 and tapping his bike, urging Navarro to stay behind him. The gesture was justified as Canet was consistently lapping under 1:42 while thec rest of the field circulated in the low 1:43s.
An equally fierce battle raged behind them as local hero Fabio Quartararo working hard to hold off the attacks of fellow KTM riders Nicolo Bulega and Andrea Migno. In true Moto3 style it all came down to the last lap, Binder defending his line from Fenati on every corner as the Italian tried everything he knew to get by.
A perfect final lap saw Binder take his second career victory by 0.099s, while Navarro was fortunate to clinch third after an aggressive move by team-mate Canet in the second-last corner.
Nicolo Bulega came out on top of the battle for fifth ahead of Quartararo with Migno, Antonelli, Jakub Kornfeil (Honda) and Andrea Locatelli (KTM) completing the top 10.
Original source: Another win for SA’s Binder at Le Mans