Harrison Barnes scored 24 points and the last-place Dallas Mavericks knocked off a title contender for the second straight night, beating LeBron James and the Cavaliers 104-97 on Monday. Wesley Matthews had 21, and rookie point guard Yogi Ferrell scored a career-high 19 in the second game of a 10-day contract, a night after hitting clinching free throws in the final seconds of a win at Southwest Division-leading San Antonio.