Valentino Rossi got to try a new Yamaha chassis during Monday's official post-race MotoGP test at Catalunya.

After enduring a torrid weekend in Barcelona, the nine-time world champion declared the new frame to be 'better' - and still has another version to try on Tuesday.

Yamaha have two new M1 frames for testing this week, handing one each to Rossi and team-mate Maverick Vinales on Monday. Tomorrow, when the team are staying on for a private test, they will switch to get a feel for the other option.

"I always struggle with this bike for turning, for the entry to the corner. I'm never very comfortable. At 100%," said Rossi, speaking in the paddock on Monday evening.

"So today we had a different chassis, a little bit, Yamaha work always very much under this point of view. And is better. I like. I prefer the bike like this. It's more easy. It's better for my style.

"For me the bike turns a bit better and I enter into the corner faster. So this is the way. You can be more precise and is also more fun to ride.

"There remain some other problems like the stress on the rear tyre that anyway is quite a lot in a track like this. So we have to continue. Try to improve. Tomorrow will be another day here. We have some other stuff to try so we hope to continue like this."

Rossi has complained of corner-entry problems since winter testing, initially believing it was due to the 2017 Michelin front tyre, while new team-mate Maverick Vinales headed every outing and won the opening two races.

But the young Spaniard has also hit major problems in Jerez and Catalunya, finishing just tenth in Sunday's race, when Rossi was eighth at a circuit he won at last season.

Edit! Difference in Catalunya race times by rider, 2016 vs. 2017. Biggest gains Dovi, Redding. Biggest losses Rossi, Pol #CatalanGP #MotoGP pic.twitter.com/RyBKd2MGiA-- Peter McLaren (@McLarenMotoGP) June 12, 2017

Did Vinales' testing speed lull Yamaha into a false sense of security regarding the 2017 chassis? Rossi pointed out the Spaniard still leads the world championship, but added that being new to the team Vinales was unaware of how the character of the Yamaha had changed.

"You know, at the end Maverick was fast and Maverick continue to like [the 2017 chassis] and Maverick is the guy with more points. So I have to speak more about me. I'm coming from another story," Rossi said.

"Maverick don't have any history with the Yamaha, coming from Suzuki, and he ride this because he think it's the Yamaha.

"But for me, because I know more the evolution of the bike, I think that that with the 2017 version we lose something. Yesterday also he was in trouble, but I think he can go fast anyway."

And how much of Sunday's woes were caused by Yamaha opting against joining the likes of Honda and Ducati at a private Catalunya test last month?

"Not all from that, but missing the test was a problem, yes."

Rossi set the tenth fastest lap time at Monday's test, 1.5s from Marc Marquez and 1.2s from Vinales - both Spaniards going out for a late time attack.

The Doctor is fifth in the world championship, but a closer 28 points from Vinales heading into next weekend's Assen round.