On the original start, Rins had destroyed the field to gain a huge lead after only a couple of corners, and the rain was falling but not heavy.
The conditions remained difficult, however, and a good few big names - including some wet specialists - found themselves sliding out.
They included a highside that skittled Marquez into the gravel from podium contention, and a high-speed tumble for Vinales after a good initial getaway.
Pol Espargaro crashed out of P4 at Turn 3 after a stunning start, but he was incredibly able to re-join the race.
Brother Aleix Espargaro (Aprilia Racing Team Gresini), Jack Miller (Alma Pramac Racing), team-mate Danilo Petrucci (Alma Pramac Racing) and Andrea Iannone (Team Suzuki Ecstar) also all crashed out and couldn't get back in it, but Rossi? At that stage, he was only getting faster as the rain was getting worse.
Eventually, however, the volume of rain was starting to beat the circuit's ability to drain and the Red Flag came out.
The race would be re-started for 14 laps, and the grid would be decided by the standings as of the last completed lap - meaning it was Rins on pole, Dovizioso second, Rossi third and Dani Pedrosa (Repsol Honda Team) lining up fourth in his final race. 14 laps and the end of an era for many...
Rossi made his move past Rins at Turn 4 - 1.5 down on 'DesmoDovi'.
However, with six to go, the gap was up to 2.4 and a lap later, the Ducati rider's lead was over three seconds. But then, the drama hit again and ‘The Doctor' was down at Turn 12 - rider ok, but lifting Espargaro and KTM up to a podium place.