The victory over the Wildcats, who are No. 7 in the NET rankings, gave the Trojans (20-9, 9-7 Pac-12) a much-needed quality win against a Quadrant 1 team to boost their NCAA Tournament chances.
The win also helped USC remain in contention for a top-four seed needed for a first-round bye in the Pac-12 Tournament.
"It's do or die," said Mathews, who is one of USC's two senior captains. "I don't have another year. Every rebound, every shot, everything matters. It's crunch time before March Madness."
USC held Arizona, the Pac-12's highest scoring team, to its lowest point total of the season. The Wildcats (19-8, 9-5 Pac-12) shot just 16-of-57 from the field (28.1%) and were only 3-of-26 (11.5%) from the 3-point line.
Okongwu finished the game with four blocks. Ethan Anderson had a season-high three steals and helped contain Arizona star point guard Nico Mannion to just 3-for-14 from the field.
"We tried to challenge everything," said USC coach Andy Enfield. "Coach [Jason] Hart had a great game plan. We executed and challenged everything. We took away the inside game."
Zeke Nnaji had 15 points and 10 rebounds for the Wildcats.
With time expiring in the first half, Okongwu hit a long shot from the opposite 3-point line at the buzzer to give the Trojans a 26-21 advantage at halftime.
The game was tightly contested prior to the shot, but Okongwu’s prayer gave USC momentum heading into the second half. It helped build a lead that the Trojans wouldn’t relinquish for the rest of the game, though USC fought off a late Arizona charge that brought the Wildcats within three points with 3:53 left.
National media outlets quickly made Okongwu's first collegiate 3-pointer viral.
"I always work on shots after practice," Okongwu said. "I took that shot and it went in. I didn't imagine it would, but I'll take it."