Maverick Vinales snatched the lead in the MotoGP drivers' standings from Yamaha team-mate Valentino Rossi with victory at the French Grand Prix, thanks to the Italian's last-lap crash.
Rossi had moved ahead from his stable-mate with just three laps to go and looked on course for a first grand prix win since Catalonia last year.
But 'The Doctor' ran wide at Turn 8 as he began to think of the chequered flag to let Vinales back into the lead, before sliding out at the penultimate corner to leave the Le Mans crowned in stunned silence.
Having picked up his first podium in Le Mans a year ago, Vinales' third win of 2017 was Yamaha's 500th in premier-class motorcycle racing.
They had earlier been rapturous as Johann Zarco briefly had them dreaming of a first French premier-class win on home soil in almost 60 years, with Rossi's late slide handing the rookie second place - his first MotoGP podium.
Vinales deserved credit for forcing his team-mate's hand somewhat, having put in a circuit-record lap time on the final lap on an afternoon which saw the benchmark steadily drop until Vinales' 1'32.309.
The top four in the championship were separated by just 10 points pre-race, but Marc Marquez also crashed out to send Vinales 17 points clear of Dani Pedrosa, who took third place after starting 13th on the grid to move into second in the standings.
ZARCO'S STAR IS BORN
Moto2 champion Zarco has already shown his premier-class potential this year, having led the season-opener in Qatar before crashing out, but he showed the consistency to match his talent this time around.
Bursting clear of Rossi and Vinales off the line, Zarco got his elbows out on soft tyres to snatch P1 for seven laps before his rubber began to give way and Vinales seized the lead.
Zarco said afterwards: "It has been a nice race, a great start. Since the beginning I was feeling strong on the start and first corner."
PLUCKY PEDROSA INTO TITLE PICTURE
Having qualified 13th, Pedrosa needed something huge to match his victory last time out.
After picking up six spots on lap one, Pedrosa was at his punchy best to take fifth place from Cal Crutchlow.
IN THE POINTS
1. Maverick Vinales (Movistar Yamaha)
2. Johann Zarco (Monster Yamaha Tech 3) +3.134 seconds
3. Dani Pedrosa (Repsol Honda) +7.717secs
4. Andrea Dovizioso (Ducati) +11.223secs
5. Cal Crutchlow (LCR Honda) +13.519secs
6. Jorge Lorenzo (Ducati) +24.002secs
7. Jonas Folger (Monster Yamaha Tech 3) +25.733secs
8. Jack Miller (Marc VDS) +32.603secs
9. Loris Baz (Avintia) +45.784secs
10. Andrea Iannone (Suzuki Ecstar) +48.332secs
11. Tito Rabat (Marc VDS) +50.036secs
12. Pol Espargaro (Red Bull KTM) +52.661secs
13. Bradley Smith (Red Bull KTM) +53.179secs
14. Sam Lowes (Aprilia) +55.432secs
15. Sylvain Guintoli (Suzuki Ecstar) +66.878secs
1. Maverick Vinales (Movistar Yamaha) - 85
2. Dani Pedrosa (Repsol Honda) - 68
3. Valentino Rossi (Movistar Yamaha) - 62
4. Marc Marquez (Repsol Honda) - 58
5. Johann Zarco (Monster Yamaha Tech 3) - 55
Rossi will be hoping for better on home turf at Mugello, although he has not won there since a run of seven-straight successes from 2002 to 2008.