Kelly Olynyk added 15 points, and Sam Dower and Drew Barham had 13 each for the Zags (20-2, 7-0 West Coast), ensuring coach Mark Few his 14th consecutive season with at least 20 victories.
Anthony Ireland made five 3-pointers while scoring 19 points to lead the Lions (8-13, 1-7), who have lost five straight and seven of eight.
It was the Zags' fourth consecutive blowout league victory, and they got the rout going early as the highest-ranked opponent to visit Gersten Pavilion since being here as the No. 5 team in February 2006. They led by 28 points at halftime and gradually expanded the margin even as Few substituted liberally.
Gonzaga stretched its lead to 81-34 with a 21-5 run midway through the second half. The Zags hit five 3-pointers, three by Barham, and David Stockton, son of Naismith Memorial Hall of Famer John, added a 3-pointer and two free throws.
The Lions were outclassed in every category while being held to their fewest points of the season. They shot 25 percent from the field and committed 14 turnovers.
Gonzaga shot 54 percent for the game, controlled the boards 46-31, and its bench outscored the Lions' reserves 47-4. The Zags owned a 30-10 edge in points in the paint and shot 50 percent from the free throw line.
The Zags have won three straight since losing to then-No. 13 Butler by one point on Jan. 19.
They shot 57 percent from the field in the first half, when the Zags led 46-18. They made eight 3-pointers, including four straight during a 15-0 run while the Lions went 6:25 without a basket. The Lions got as close as six points when Ireland and Ashley Hamilton combined to score 10 straight points before Gonzaga cranked up its long-range shooting. Hamilton had the Lions' only basket over the final 9:52 of the half.
Seventeen NBA scouts were on hand, including ones from the Lakers and Clippers.