Jefferson scored eight points and Williams had seven in the third quarter, leading the Jazz (2-0) to their second win in five days over the Blazers (1-3).
LaMarcus Aldridge scored 22 points, including going 12 of 14 from the free throw line, in 33 minutes for Portland.
The game was played in Memorial Coliseum, the Blazers' home facility from 1970-94 before the team moved into the Rose Garden.
Utah shot 68 percent from the field in the second half and finished 36 of 71 for the game.
C.J. Miles scored 10 of his 14 points in the second half for the Jazz, who used 15 players in the game.
Wesley Matthews, Portland's leading scorer in two of its first three preseason games, had 16 points. The 6-foot-5 Matthews, a rookie with Utah last season, was signed as a free agent by Portland this summer.