Dirk Nowitzki scored 17 points, Devin Harris added 14 and Jerry Stackhouse had 12 for the Mavericks, who are 3-4 with one exhibition game remaining against San Antonio. The Cavaliers finished the preseason 2-8, with LeBron James getting 13 points -- 6 in the opening 4 minutes -- in 27½ minutes of playing time.
Drew Gooden had 10 points for Cleveland, which gave more playing time to its bench than Dallas did.
Cleveland didn't score after Shannon Brown's 15-footer with two minutes remaining put the Cavaliers up 81-79. Harris' two free throws with 1:23 remaining tied it, and Diop gave the Mavericks the lead by hitting a free throw with 45 seconds to go. Croshere made the back end of two free throws with 43 seconds to go, and Brown then dribbled the ball out of bounds 14 seconds later.
Diop kept the Cavaliers from getting the ball back for a final attempt to tie or win it by rebounding Harris' missed jumper with five seconds to play.
The Cavaliers are trying to build a fan base in Pittsburgh, a two-hour drive from Cleveland. Cavs games are regularly televised locally, and the club has begun marketing in a region where the University of Pittsburgh has sold out its home games for four seasons.
While Steelers quarterback Ben Roethlisberger was prominent in his center court seat and coach Jamie Dixon of Big East preseason favorite Pitt sat a few rows behind the Cavs bench, the person attracting the most attention in a half-filled Mellon Arena was Mavericks owner Mark Cuban.
Cuban brought the Mavericks to his hometown for the first time and seemed to be everywhere, shaking hands, signing autographs and posing for pictures. He spent part of the first half behind the microphone for the game telecast on the high-definition TV channel he owns.