Jason Terry added 19 points off the bench for the Mavs, who eliminated the venerable Spurs in five games and move on to face either Denver or New Orleans.
Dallas made its statement early in the game with a 14-4 run highlighted by five consecutive points by Nowitzki and one of Jason Kidd's four three-pointers. The Mavericks never trailed in the game and led by as many as 16 points.
Every Dallas starter finished in double figures.
"They are a better team than we are right now," Spurs Coach Gregg Popovich conceded as his star, Tim Duncan, failed for the first time ever to get past the first round of the playoffs.
Duncan hit a fadeaway jumper in the third quarter to tighten the game to 63-59; however, Dallas followed up with nine consecutive points and accelerated to a 72-59 advantage.
Duncan led the Spurs with 30 points and eight rebounds. Tony Parker scored 26 and chipped in with a dozen assists.