Connor Harding added 10 points for the Wolverines (7-1), who beat the Cougars for the second time in school history — the first win was in 2016.
Utah Valley allowed BYU to make just five total baskets during the final eight minutes of regulation and overtime. The Wolverines forced 15 turnovers, including 11 steals.
“We adjusted to how they play,” Aimaq said. “We have a little saying called EFN: energy, fight, nastiness. We brought that tonight and came out with a win.”
Alex Barcello led BYU (6-1) with 17 points and 11 rebounds, Spencer Johnson added 15 points and nine rebounds, and Seneca Knight and Te’Jon Lucas scored 10 points apiece.
The Cougars shot a season-low 32% from the field.
“We have a lot to learn and a lot to grow and some younger guys who need to grow fast and we will,” BYU coach Mark Pope said. “We’re not going to move through this gauntlet without being exposed a couple of times. It’s good for us and it’s helping with what we need to do.”
After Johnson sent the game to overtime with a layup just before the buzzer, Utah Valley took control in the extra period. Aimaq hit a 3-pointer with 2:43 left to put the Wolverines ahead to stay, kicking off a 10-0 run over the next 2 minutes. His free throw made it 67-59 with 43 seconds remaining.
Utah Valley held BYU without a field goal over a 2 1/2 minute stretch.
“We have a group that loves defense,” Wolverines coach Mark Madsen said.
Utah Valley went 12 of 16 from the free-throw line in overtime and attempted only five shots.
Lucas hit a pair of free throws to give BYU its largest lead at 50-43 with 4:13 remaining in regulation. Then the Cougars went cold. Harmon, Aimaq and Tim Fuller scored on three consecutive possessions to put Utah Valley ahead 54-51 with 16.7 seconds left.
Utah Valley missed its first 13 field-goal attempts before Harmon scored back-to-back fast-break layups off steals eight minutes into the first half.
BYU wasn’t much better early. The Cougars missed 14 of their first 18 shots from the field and shot 31% overall in the first half.
BYU lost senior forward Gavin Baxter to another season-ending injury. Baxter played only four minutes before he tore the ACL in his left knee early in the first half.
For Baxter, this is the third consecutive season he has suffered a major injury. He has appeared in 15 games for the Cougars in that stretch.
Utah Valley moved to 4-0 in overtime games this season. The Wolverines also beat Pepperdine, Long Beach State and Denver in OT.
Utah Valley’s players were confident after time expired in regulation.
“Nothing was discussed,” Aimaq said. “All we said was, ‘If it’s going to overtime, we’re going to win.’”
Utah Valley: Few shots fell for the Wolverines over 45 minutes, but they hung tough by playing rugged defense and crashing the glass. Utah Valley will be a tough out in the Western Athletic Conference.
BYU: The Cougars started slow on offense for a second straight game. Once again, tough defense gave BYU time to hit a few shots at critical junctures after halftime. The Cougars could not get anything done until Johnson’s tying basket, missing 11 straight shots over an eight-minute stretch, and faltered again in overtime.
An ugly loss against an underrated Utah Valley team will drop BYU in the AP Top 25.
Utah Valley hosts Yellowstone Christian on Friday.
BYU visits Missouri State on Saturday.