Jordan Monteith hit two free throws to cut the Pacific lead to five at 20-15, but the Tigers responded with an 11-2 run.
Thompson was 7 for 7 from the field, 5 for 5 from the line and grabbed nine rebounds to lead the Tigers (2-1). Ray Bowles added 12 points and Dulani Robinson chipped in 10 points and dished off 11 assists while Sami Eleraky pulled down 12 rebounds.
Jarron Crump came off the Pacific Union bench to score 13 points. Greg Brown added 10.
The Tigers shot a crisp 56.5 percent from the floor and were 6 of 18 (33.3 percent) from long range. Pacific dominated the boards, pulling down 46, 20 off the offensive glass. The Pioneers grabbed 24 rebounds total.