Think that last free throw was meaningless for Duke as it beat Utah in the Sweet 16? Thousands of gamblers in Las Vegas disagree.

The free throw allowed the top-seeded Blue Devils to cover a five-point spread on Friday night, topping the Utes by six at 63-57 and flipping wagers on a game many thought was already over.

Luckily for gamblers, it appears most were backing Duke, laying five points at Las Vegas sports books operated by Caesars Entertainment, MGM Resorts International and the Wynn Las Vegas.

That bet was looking OK for wagers on the No. 5 seed Utah as the game was wrapping up. The buzzer had sounded, and the players had already even finished their customary postgame handshake. Some Utah players were already heading off the court.

Done deal, right? Not quite. The whistle sounded.

The officials had reviewed a call and determined that Utah, which was trying to foul, had successfully done so with 0.6 seconds left on the clock.

The score at that moment was 62-57, a would-be push on bets taken at a five-point spread, and a loss for some Duke bettors who gave up 5½ points.

Quinn Cook missed the first free throw, then made the second to finish the game at 63-57. Six point margin, Duke covers.

It's not immediately clear how much money swung on the free throw, but casinos appeared to be on the losing end. According to wager reports compiled by Pregame.com, nearly three-fourths of spread bettors were backing Duke, with nearly 108,000 wagers on the game.

In gambling parlance, the outcome is what's known as a backdoor cover — determined in the final moments of the game, and often meaningless to the outcome of the game itself. It happens frequently enough.

In 2013, Ohio State covered the spread against Northwestern after a fumble recovery in the end zone in the final moments, shifting about $100 million in bets.

In 2012, Las Vegas oddsmakers estimated $300 million or more changed hands when a controversial call from a replacement referee used during a labor dispute decided a Monday night NFL game between the Packers and Seahawks.

Shooting pains

The South Regional of the NCAA tournament is the only one being played in a football stadium.

Is that the reason for such poor shooting in Houston?

The games are being played in NRG Stadium, which is home to the Houston Texans, and the setup, with no walls or bleachers directly behind either basket, challenges players' depth perception. There are black curtains behind each goal, but they are far from the baskets.

"It's tough being out there on a court where there's so much room behind the basket," said Utah's Brekkott Chapman, whose team shot just 35 percent in a loss to Duke on Friday night. "But it's something that you got to adjust to quickly if you want to succeed in this."

The other regionals are being played at Staples Center, home to the Los Angeles Lakers and Clippers; Quicken Loans Arena, where the Cleveland Cavaliers play, and the Carrier Dome, home to Syracuse basketball and football games. Even though some football games are played at the Carrier Dome, the setup for the tournament is that of a traditional basketball arena.

"It's an interesting environment," Utah coach Larry Krystkowiak said of NRG Stadium. "It's not a basketball arena. It's the only regional that's played in a venue like this. Everybody else is a normal-sized arena. It's not [just] our issue. It's Duke's issue as well as everybody else."

Duke's Matt Jones said the setup made him feel like he was on an island.

"You can definitely feel alone up there," he said. "I've never been in a stadium like this, and for me, personally, it's different. On the outside looking in I can see how you can feel alone. Everybody's so far away from you and the depth is crazy. It was different, but you have to get used to it real fast."