Rossi wins after clash with Marquez

Marquez had made an early break and dominated most of the race, while Rossi fought his way through from eighth on the grid.

But just before the race, Marquez decided to switch from Bridgestone's extra-hard - prepared especially for the tyre-hungry Termas de Rio Hondo track - compound to the hard, putting him on the opposite strategy to the Yamahas.

As Marquez's tyres and pace faded, Rossi moved up to second place and began to chip away at what had been nearly a five-second lead.

With three laps to go, the leaders were together. Rossi made his first move into Turn 1 on the penultimate lap, but Marquez was able to cut back inside and retake the place.

Rossi then tried again at the end of the back straight, as Marquez slid sideways under braking for the tight right-hander.

The Honda got partially back alongside on the corner exit and they made contact twice, with the second hit sending Marquez to the ground as he clipped the back of the Yamaha under acceleration.

Marquez tried to get his Honda restarted but to no avail.

Although race direction investigated the tangle, it was quickly announced that no action would be taken.

Andrea Dovizioso claimed his third second place for Ducati in as many races.

He battled through to second early on, then initially stayed with Rossi as both closed on Marquez, before falling away from the Yamaha.

Cal Crutchlow snatched his first podium for LCR Honda with a last-corner move on the second Ducati of Andrea Iannone for third place.

Crutchlow had also spent a spell in second following a ferocious early dice with the factory Ducatis and Yamahas, and he then dropped away from Rossi and Dovizioso before winning a final tussle with Iannone.

It was a muted race for Jorge Lorenzo. As he charged from fifth to second in the opening laps it looked as though he would be Marquez's main rival, but he was then elbowed down to sixth and gradually lost touch with the battles ahead.

By the time he started closing on Crutchlow and Iannone, there was no time left to regain ground.

Although Aleix Espargaro put Suzuki second on the grid, the bike's lack of straightline speed was always going to make hanging on for a podium tough.

Espargaro put up a spirited fight - swapping the lead with Marquez a couple of times on lap one and then having a few exchanges of second place with Lorenzo, but he then fell back.

He ended up seventh, between the Tech 3 Yamahas of Bradley Smith and Pol Espargaro.

Scott Redding fended off a late surge from the second Suzuki of Maverick Vinales for 10th.

Danilo Petrucci dropped back from seventh on the grid to 11th, with Jack Miller producing his best MotoGP ride so far to beat a train of bikes to 12th.

Hiroshi Aoyama crashed the second works Honda out of 14th place on the final lap.

Yonny Hernandez was the other retirement, parking his Pramac Ducati with a fiery failure.