The visiting Mavericks never trailed, and shot a blistering 55 percent from the field to hold off several second-half rallies by the Cougars. Playing aggressive, physical defense, the Mavericks committed 28 fouls, but also scored 32 points off BYU's 20 turnovers to pick up the postseason win as five-point underdogs.
Mika (29) and Emery (24) combined for 53 points for BYU, but the only other Cougar in double figures was Haws, with 11.
Drew Charles (28), Kaelon Wilson (20) and Kevin Hervey (20) scored in double figures for UT Arlington, which played without second-leading scorer Jalen Jones, out with a hand injury.
Trailing 62-55 at halftime after UTA shot 64 percent in the first half, the Cougars misfired on seven of their first eight possessions of the second half. That enabled the Mavericks to build the lead to 71-58 and take the crowd out of the game. Emery hit a 3-pointer with 13 minutes remaining to cut the deficit to eight and the crowd got into it momentarily, but UTA answered with a layup and free throws after an offensive rebound to regain control and coasted to the victory.
In a wildly entertaining first half, BYU shot 59 percent but still trailed by seven.
Mika scored 23 first-half points, and Emery had 15 at the break as the duo accounted for 69 percent of the team's points the first 20 minutes. It was the 35th straight game Mika has scored in double figures, dating back to the final game of his freshman season in 2014.
Emery made one of two free throws with 3:42 left before halftime to knot the score at 48, but UTA scored on its last seven possessions of the half to take the seven-point lead and the Cougars got no closer. The run included a banked-in hook shot and a basket that Hervey was credited for that was accidentally tipped in by the Cougars.
Davin Guinn made his first start, replacing the injured Bryant (knee) in the starting lineup. Reserve guard Zach Frampton also made a 3-pointer in the first half, his first field goal of the season.