Marc Marquez believes Casey Stoner's return to MotoGP testing with Honda will be a major boost for his and Dani Pedrosa's title bids.
Two-time world champion Stoner retired from MotoGP last season, but has agreed to help develop both Honda's factory 2014 MotoGP bike and the production racer it is selling to customer teams next year.
He carried out his first test at Motegi earlier this month. Marquez believes Stoner's presence offers major advantages over the Japanese test riders Honda usually calls up.
"For us it's quite important," said Marquez of Stoner's test. "It pays to ride that bike.
"I didn't have information about the Motegi test because I didn't speak with the Japanese guys, but I would like to at Indianapolis.
"I feel Casey is so fast and he put the bike on the limit for sure in that test.
"I think it's important for Honda, for Dani and for me. He tested that bike and all the limits.
"Sometimes you can test some parts but if you are not doing the correct lap times or you didn't push a lot, then you cannot feel good."
Rookie sensation Marquez currently leads the MotoGP standings by 16 points over Honda team-mate Pedrosa, with reigning champion Jorge Lorenzo a further 10 points back. Both Lorenzo and Pedrosa's seasons have recently been disrupted by injuries.
Stoner has focused on circuit racing since quitting MotoGP, and is driving for top V8 Supercars team Triple Eight's V8 Development Series squad.
Despite constant rumours of a MotoGP comeback, Stoner reiterated after his Honda test that he has no interest in even occasional appearances.
"I'm happy with how the test went, but it doesn't change my mind about the wildcards - this is not something I am planning to do," he said.