Valentino Rossi worried by Honda wet pace in Jerez MotoGP practice

Led by Dani Pedrosa, Honda riders filled four of the top five places in first practice at a wet Jerez on Friday morning.

Maverick Vinales was the best of the Yamaha riders in 10th, nine tenths adrift, with championship leader Rossi a further six places and seven tenths further back.

While Marc Marquez, Cal Crutchlow and Jack Miller all won races on Hondas in mixed conditions last year, Rossi believes Yamaha had the pace advantage, which looks to have shifted.

"We suffered a bit, we didn't find the right setting - the [2016] bike on the wet, everything was more natural, more easy," said Rossi.

"It looks like we have to work a bit more in those conditions, I was not fast enough.

"[The problems are] very similar to the dry. I am not able to enter fast enough and also we spin very much on acceleration.

"The performance of the Honda makes us quite worried today, because in the wet like in Argentina in practice and qualifying they have found something better than last year.

"Last year when it was wet, I was very fast and the Hondas were more in trouble.

"This year it's like the Hondas are very fast and the Yamahas are more in trouble.

"We need to understand the right balance for the wet."

Yamaha tested at Le Mans earlier this week, which included running in the wet, but Rossi believes the grip of the resurfaced asphalt at the French track masked Yamaha's problems.

Vinales agreed Yamaha has work to do in the wet, but felt changes made during the test meant the bike was "improved a little bit".

"I think the bike was more constant," he said.

"I think we are still able to improve the electronics, so I was really happy this morning in the wet conditions."

MARQUEZ AGREES HONDA GOOD IN THE WET

Marquez took pole in the wet qualifying session at Termas de Rio Hondo last month, and headed to Jerez off the back of winning in the dry at Austin but unsure why the Honda was so quick.

He acknowledged the RC213V was working well in the wet, taking away the impact of Honda's acceleration deficit in the dry.

"In the wet it's a good bike, for some reason," he said.

"Already in the wet in Argentina, you could manage well to find the grip.

"You cannot use all the torque on the exit of the corner, and then we lose zero on acceleration - we don't have wheelie in the wet, the spin is the limit of the acceleration.

"We are not losing on acceleration and we keep our strong points also in the wet, which is the braking point and turn-in."