Riverside Poly (15-13), which finished fourth in the Ivy League, built a 40-17 halftime lead. The Bears scored 21 second-quarter points to break the game open.
The Nitros finished their season at 13-14 after finishing fifth in the Pacific League and grabbing an at-large CIF berth.
Riverside Poly, which had lost four games in a row prior to Thursday, will face top-seeded Hart in a first-round contest at 7:30 p.m. Saturday.
First-year Glendale Coach Tania Adary said the Nitros, who ended their season with three consecutive defeats after winning their previous three, had to overcome obstacles just to extend their season in mid-February.
"We just had an up-and-down season, but nobody thought we would get this far," said Adary, a former Nitros athlete who inherited the team last summer from Fred Babadjanians. "We wanted to make the playoffs and my seniors gave their all.
"It looked like this game would be an even matchup, but we started off slow before getting a few fast-break points. We just couldn't convert on the offensive end [in the second half]. We hit some shots, but it was too late."
Glendale got a team-high 18 points from senior guard Melia Basavand, who finished with four three-pointers. Senior guard Lara Kadehjian added 15 points for the Nitros, who got seven rebounds from Rebecca Krikorian in her varsity debut.
CHARLES RICH covers sports. He can be reached at (818) 637-3228 or by e-mail at charles.rich@latimes.com.