MotoGP world champion Jorge Lorenzo has tipped Honda's new signing Casey Stoner as his biggest rival for the 2011 title.
While Stoner switches from Ducati to Honda next year and Valentino Rossi leaves Yamaha for Ducati, Lorenzo will stay on to defend his crown with Yamaha.
Asked by Gazzetta dello Sport whether he feared the Rossi/Ducati or Stoner/Honda partnership most, Lorenzo said he believes Honda will give Stoner a quicker package than Ducati will provide for Rossi.
"As things stands now I'd say Casey/Honda [is the bigger threat]," said Lorenzo.
"The Japanese manufacturer is ahead compared to Ducati, but then everyone would say that after the Valencia test.
"Experience, however, suggests to wait for the first race of the year in Qatar. The red bike has great potential and has demonstrated that with Stoner these years."
Lorenzo also believes Stoner will prove to be a tougher long-term opponent than either his Honda team-mate Dani Pedrosa or Rossi.
"Pedrosa lacks something in side-by-side racing, while Rossi... well, it's difficult to find shortcomings with him," said Lorenzo.
"I'd say his limit is age. He's been at the front for many years, and it can't be easy to be up there for so long. For sure, he's super-motivated at the moment.
"In my opinion Stoner has more talent than anyone else. The way he rides is impressive, but he isn't consistent, he crashes too much. But when he's calm and focused it's tough to beat him."
Former World Superbike champion Ben Spies is moving from the satellite Tech 3 squad to Yamaha's works team next year, and Lorenzo believes his new team-mate will be another major challenge.
"He's really phenomenal, but his presence gives me huge motivation," said the Spaniard.