DAYTON, Ohio (AP) - Almost nothing went wrong for Iona in the first 16 minutes of its first-round game against BYU.

After that, almost nothing went right.

The Cougars staged the biggest comeback in NCAA tournament history Tuesday night, overturning a 25-point deficit to beat the Gaels 78-72.

"We weren't good enough in the second half to withstand that comeback," Iona coach Tim Cluess said.

Ahead 49-24 after less than 14 minutes, the Gaels were outscored 37-13 over the next 17-plus minutes as the Cougars stormed back.

Iona, an undersized team that doesn't have a starter taller than 6-foot-7, hit 24 of 35 (69 percent) shots from the field while building the big lead. From there to the finish, the Gaels also took 35 shots - and made just seven (20 percent).

"When we're not making shots, it's kind of hard to be able to press like we were in the first half,'' said star point guard Scott Machado, who had 15 points and 10 assists. "It's hard for us to get stops at that end because we're so small.''

Cluess said there was no mystery to what went wrong: A good-shooting, short team that doesn't hit shots is just a short team.

"When we don't make shots, we're not the same type of team,'' he said. "We're a small team. They did a great job of getting it inside, kicking it back out and making plays."

So now it's the Cougars (26-8) who advance to play third-seeded Marquette on Thursday in Louisville, Ky.

It marked the biggest comeback in an NCAA tournament game, the organization said. Previously, the largest deficit overcome was 22 points in 2001 when Duke fought back to beat Maryland 95-84 in the national semifinals.

Iona (25-8) came in as the nation's top-scoring team at 83.2 points per game and didn't disappoint - at least while running up 55 points in the opening 16 minutes. But the Gaels didn't score in the final 4 1/2 minutes of the first half and never got untracked again.

BYU held the Gaels without a point for 9:20 in a 17-0 run to narrow the deficit to 62-61 midway through the second half. Iona was stymied by the Cougars' trapping halfcourt defense.

But the Gaels still had the game within reach.

Machado's three-point play pushed the lead to 70-64 with 5 minutes remaining before Noah Hartsock, who led BYU with 23 points, hit an outside shot. After two missed foul shots by the Gaels, he hit another short turnaround jumper to cut the lead to two.

With 2:26 left, Hartsock popped out on the right wing to hit a go-ahead 3-pointer. It was the Cougars' first lead of the game.

Brandon Davies, who had 18 points and 15 rebounds for the Cougars, added two free throws in the final minute before Brock Zylstra scored on a layup in transition and was fouled, completing the three-point play and ending Iona's hopes.

"We just were more aggressive,'' Zylstra said. "We were doing to them what they were doing to us in the first half.''

Jermel Jenkins had 13 points, Mike Glover 12 and Sean Armand 10 for the Gaels, thwarted in trying to get the school's first official NCAA tournament win in eight tries. The Gaels won a game in the 1980 tournament but it was vacated due to NCAA violations.

Now they'll be tormented by what might have been.

"It's going to be one that we have to live with the rest of our lives, that we had an opportunity to win and advance,'' Cluess said. "It's a tough one we let get away. No excuses.''