Jefferson scored 21 points, grabbed 10 rebounds and pushed Utah to a 15-point halftime advantage.
The teams will meet again Saturday in Portland.
The game was marred when Portland guard Wesley Matthews suffered a severely sprained right ankle and had to be helped off the court during the third quarter. He was injured when he slipped while driving to the basket. X-rays were negative.
Rookie Damian Lillard led Portland with 26 points and Lamarcus Aldridge had 16 points to go with 10 rebounds.