Rob Kardashian -- I'm Going to Win "Dancing With the Stars!"

Rob Kardashian is like one of Pavlov's dogs ... a little praise from "Dancing with the Stars" judge Carrie Ann Inaba has him thinking he's got a shot to win the whole competition.

After Rob danced the jive on Monday ... Carrie Ann said, "It's official. Rob Kardashian is a better dancer than Kim Kardashian!"

Now sources close to the show tell us Rob is hitting the gym daily, practicing harder than ever -- and sucking up to his partner/teacher Cheryl Burke by bringing her lunch each day.

Rob's new attitude is a 180 from a few weeks ago -- when he was a total slacker.