Gresini Ducati MotoGP rider Alex Marquez has been taken to hospital as a consequence of a terrifying Catalan Grand Prix collision triggered by an issue on rival Pedro Acosta's KTM.

Acosta and Marquez had established themselves as the race's main contenders and had just settled in after a Turn 1 duel from the lead when Acosta's KTM appeared to cut out sharply on the run to Turn 10, with Marquez caught out behind him.

Marquez had just enough time to avoid slamming directly into the rear of the KTM, but in darting to the right - and taking off a big chunk of his aero against Acosta's bike - he consigned himself to a terrifying ride through the grass, a total passenger.

Marquez luckily avoided the wall but took a big hit against the ground once the bike spat him off, while the Ducati then proceeded to shred itself as it cartwheeled through the gravel.

The collision pelted Raul Fernandez and Johann Zarco behind them with carbon fibre debris (both left in significant pain), and the Ducati's subsequent somersaulting tore off the front wheel - which bounced terrifyingly in the braking zone, eventually making contact with the front wheel of fellow Ducati rider Fabio Di Giannantonio, forcing him to also crash.

With the red flag coming out, Marquez was treated at the site of the incident in the aftermath - and taken to the medical centre.

From there, he was forwarded to the local hospital for further evaluation.

Only Marquez and Enea Bastianini, who had exited the race earlier with another KTM technical issue, were ruled out of the restart - with both Acosta and Di Giannantonio managing to get their damaged bikes to the pits, Acosta relying on a push from KTM stablemate Brad Binder (whose bike seemingly cut out during the initial start) and then the Pramac Yamaha duo of Jack Miller and Toprak Razgatlioglu.