The loss drops the Lancers to 7-3 overall, 1-1 PacWest.
The 'Lopes, who haven't lost since Nov. 14, improve to 13-2, 4-0.
It was a classic game from the start that had nine ties and 13 lead changes, 10 of them after halftime and six of them in the final 5:22 of regulation.
Pickrel hit four 3-pointers. His first came at the halftime buzzer to give Grand Canyon a 37-31 halftime lead. His second came with 1:48 left in regulation and gave the 'Lopes a 67-65 lead. His third one forced overtime, and his final one was the game-clincher.
After Pickrel made it 67-65, Ivan Patterson made 1 of 2 free throws but the Lancers got the offensive rebound off his miss and he converted a layup with 1:13 to play to give the Lancers a 68-67 lead. After an offensive foul by Grand Canyon, Evans cleaned up a Wong miss with an offensive putback to push the Lancer lead to 70-67 with 14 seconds left, setting up Pickrel's heroics.
The Lancers played it perfectly and with the 6-foot-8 Evans in his face Pickrel launched a shot from the right wing that banked off the glass and in, tying the game. The Lancers didn't get a good look in the final 2.5 seconds.
Evans gave the Lancers a 72-70 lead with a layup two minutes into overtime, but Pickrel answered on the ensuing possession and the Lancers never could get the lead back. They trailed 75-74 and had the ball with 28 seconds left, but Cosentino's 18-foot jumper from the top of the key with nine seconds left bounced off the iron and Joshua Lowery made two free throws.
Anthony Romero's attempt at a game-tying 3-pointer was on line but grazed the front of the rim as time expired.
Killian Larson led all players with 22 points and 12 rebounds before fouling out.
The Lancers shot 50 percent from the floor and held Grand Canyon to just 36.6 percent but were undone by 20 turnovers that led to 22 GCU points. The 'Lopes also grabbed 20 offensive rebounds and out-rebounded the PacWest's top rebounding team 41-36.