Oregon State (No. 22 AP), seeded fifth in the regional, played much of the second half without all-America guard Gary Payton, who fouled out with 2 minutes, 18 seconds left after scoring only 11 points. Still, the Beavers took a 53-51 lead when Teo Alibegovic hit a short hook shot with three seconds left.
But Ball State's court-length pass went out of bounds off an OSU player and the 12th-seeded Cardinals kept possession under their basket with two seconds left. McCurdy, who finished with eight points, took the inbounds pass near the baseline, hit the five-footer as time expired and was fouled by Karl Anderson.
"He (Hunsaker) told me I was going to win the game," McCurdy said. ''Throughout the season, I've been faced with situations like that. Today was just the same thing."
Chandler Thompson tied a career high with 24 points for Ball State, including two free throws that tied the score at 51 with 41 seconds left.
Ball State (25-6) advanced to a second-round game against Louisville. Oregon State, the regular-season co-champion of the Pacific Ten Conference, finished 22-7.
Payton, who came into the game averaging 26.1 points, didn't score for the first 14 minutes and picked up three fouls in the first half. He got No. 4 with 17:25 left and was benched for the next 10:25.
"I had all my shots. I just missed them," Payton said. "The ball did not go down. I can't have a good game every game."
Oregon State lost in the first round for the third year in a row.
Nevada-Las Vegas 102, Arkansas-Little Rock 72 - Stacey Augmon had 16 points and six teammates also scored in double figures as UNLV (No. 2 AP and UPI) rolled to victory over Arkansas-Little Rock.
UNLV, the top seed in the West, broke the game open with a 15-0 run late in the first half to open a 22-point lead against the No. 16 seed.
The Runnin' Rebels (30-5) led by as many as 34 points before coach Jerry Tarkanian rested his starters midway through the second half.
Arkansas-Little Rock, eliminated in the first round of the NCAA tournament for the second consecutive year, ended the season 20-10.
UNLV's pressure defense was the difference as the Rebels held Arkansas- Little Rock to only one basket in the last 8:24 of the first half. The Trojans shot only 23 percent for the half, and made only 6 of 13 free throws.
The Rebels, winning for the 16th time in their last 17 games, never trailed after Little Rock tied the score at 4 with 17:50 remaining in the first half.
Augmon scored 12 of his points in the first half to lead seven UNLV players in double figures.
Louisville 78, Idaho 59 - Jerome Harmon scored eight points and Felton Spencer added seven to spark a 26-2 Louisville run late in the first half that buried Idaho.
Everick Sullivan led the Cardinals' balanced scoring with 18 points, followed by Spencer with 17, LaBradford Smith with 16 and Harmon with 15.
Louisville (27-7) trailed, 17-10, midway through the first half before taking charge.
The Cardinals (No. 16 AP and UPI), seeded fourth, used two fastbreak baskets in scoring 12 consecutive points for a 22-17 lead.
After Sammie Freeman scored for Idaho, Louisville scored the last 14 points of the half, including a three-point play by Smith, for a 36-19 lead. The Vandals, who finished 25-6, drew no closer than 11 points in the second half.
Idaho, the Big Sky Conference champion, had a 10-point run early in the game to open a 16-8 lead, thanks to the inside scoring of Riley Smith, who had 10 of the Vandals' first 12 points.
But Louisville then tightened its interior defense, and Idaho did not have effective outside shooting, hitting only one field goal over the last 11:59 of the half.
Idaho's Riley Smith picked up his third foul with 5:46 left in the half and sat the rest of the half, leaving the Vandals without an effective offensive threat. Smith boosted his scoring total to 28 before fouling out with 4:32 left.
Ohio State 84, Providence 83 - Ohio State rallied from a 12-point deficit in the last six minutes of regulation, and freshman Jim Jackson scored six points in overtime as the Buckeyes outlasted Providence.
Freshman guard Alex Davis, who led Ohio State (17-12) with 24 points, made two free throws with 17 seconds left in overtime for an 82-78 lead.
After a rebound basket by Providence's Abdul Shamsid-Deen, Jackson made two free throws with four seconds left for an 84-80 advantage.
Eric Murdock's three-pointer at the buzzer for Providence (17-12) produced the final margin.