Valentino Rossi began the Catalunya MotoGP from his best grid position of the season, felt comfortable with his Yamaha and was 'very optimistic' for the race.

But the Italian star wouldn't get beyond Turn 10 of the second lap after being caught up in Jorge Lorenzo's accident.

Rossi was behind the Repsol Honda rider when he fell, taking out second place Andrea Dovizioso and then Maverick Vinales.

The #46 tried to avoid the mayhem but was then also struck by Lorenzo's bike.

"It's a great, great, great shame because today I felt very good because I arrive at the race from a good weekend. We worked well during practice. We learned something important and I felt comfortable with the bike," Rossi said.

"Also this morning with the medium tyre I have a good pace, I was constant, I felt good in braking and I enjoyed riding the M1. So I was very optimistic for the race.

"Sincerely, in the first two laps, I felt better also because with more temperature the medium tyre was working very well. We stayed until 9pm yesterday to make the right tyre choice and I think we had the right tyre choice so I think that I can fight for the podium.

"But I was behind Petrucci, I was a bit faster than him and I wanted to try to overtake. But I overtook in the wrong moment because I arrived faster to Turn 10 and after I saw the crash in front and unfortunately I cannot avoid Jorge's bike.

"I tried not to crash but the bike came below my tyres and at the end I also crashed.

"I have a bit of pain in my ankle because my foot remained between the two bikes, but it's like this. This is racing and sometimes it happens.

"After this weekend there remains a big desperation because we did only one lap, but on the other side some positive vibes because compared to Mugello we are a lot more competitive.

"The bike worked better, also we worked better during the weekend. We tried the maximum from all points of view, so now we need to rest one week and wait for Assen with a good feeling from Barcelona."

Before the Netherlands, Rossi - fifth in the world championship - will be back on track for Monday's official test in Barcelona.