HATTIESBURG, Miss. -- Brock Zylstra's fifth 3-pointer of the first half swished through the net and BYU's bench broke out in wild cheers.
Tyler Haws led the Cougars with 25 points, but it was Zylstra's 23 points -- including 18 in the first half -- that sparked BYU (24-11) to the easy victory. The senior hit 7 of 12 shots, including 5 of 9 from 3-point range. He came into the game averaging 7.3 points.
"You have Tyler and Brandon (Davies) - they get a lot of attention," Zylstra said. "I was the beneficiary of that. Just standing on the outside and they started falling. After a while, I wanted them to give me the ball every time."
Southern Miss (27-10) lost for just the second time in two seasons at Reed Green Coliseum. The Golden Eagles were led by Daveon Boardingham's 18 points while Jerrold Brooks added 13.
Southern Miss shot just 21 of 63 (33.3 percent) from the field and its zone defense couldn't contain BYU's shooters. The Cougars shot 11 of 27 (40.7 percent) from 3-point range.
"When we see zone, our eyes light up," Zylstra said. "Even though they're active in their zone and do a good job, we were feeling it tonight and shot the ball pretty well."
Davies scored 12 points and grabbed 13 rebounds to lead a BYU frontcourt that outmuscled Southern Miss. The Cougars had a 47-42 rebounding advantage.
"We were able to control the boards," BYU coach Dave Rose said. "It was a great team effort. Everybody gave us what they needed to give us to get this done."
BYU (24-11) went on an 11-0 run early in the first half and never trailed again, leading by double digits the entire second half. The Cougars were spurred by Matt Carlino's deep 3-pointer just before halftime that pushed their advantage to 40-29.
"Our guys got a lot of energy from that," Rose said.
Carlino scored 15 and had nine assists.
The Cougars will next face either Providence or Baylor in the semifinals of the NIT at Madison Square Garden in New York.
Southern Miss jumped out to an early 5-0 lead, but that was the end of the good news for the Golden Eagles.
BYU scored the next 11 points and never trailed again. Every time Southern Miss gained some momentum, Zylstra or Haws would respond with a timely basket. The Cougars hit seven 3-pointers in the first half.
Southern Miss coach Donnie Tyndall said he expected Haws, Davies and Carlino would give the Golden Eagles' defense trouble. But Zylstra's night was the difference.
"BYU is a really, really good team," Tyndall said. "In watching tape coming in we realized they were deceivingly athletic and they were a very good shooting team. We called them the 3-headed monster. Tonight, they added a fourth."
Southern Miss has been undersized all year -- with 6-6 Jonathan Mills and 6-7 Boardingham manning the post - but has been able to use its quickness to mitigate that disadvantage.
The problem for the Golden Eagles was that the Cougars were both tall and quick and they had trouble getting clean looks. Leading scorer Dwayne Davis finished with just eight points in his final college game on 4 of 16 shooting from the field.