QB Mitchell Gale got ACU on the board with a 3-yard TD pass to tight end Ben Gibbs at the 10:27 mark.
UCM answered with two touchdown passes from Eric Czerniewski, the first to WR Jamorris Warren for 15 yards at 7:32 and the second for 20 yards to TE David Cannon.
Cannon's was the first of three TDs for the two teams in the final 95 seconds of the quarter.
Both of ACU's scores came on one-play drives. On the ensuing play from scrimmage following Cannon's TD, Gale completed a pass in the left flat to WR Kendrick Johnson, who spun out of a tackle and ran 58 yards for a score.
ACU's defense stopped UCM on its next possession, and an 8-yard punt under heavy pressure gave the Wildcats the ball back at the Mules' 20-yard line. Gale completed a 20-yard TD pass to wide-open WR Raymond Radway on the next play, then ran in the two-point conversion himself to bring ACU to within 14 at 35-21 with 10 seconds left.
At the half, UCM led in total yards (303 to 200), passing yards (286 to 158) and first downs (13 to 11). ACU had the edge in rushing yards (42 to 17).
Gale completed 15 of 23 yards for 158 yards, one interception and three TDs. Daryl Richardson and Darrell Cantu-Harkless shared the ACU rushing lead with 19 yards each. Kendrick Johnson was the Wildcats' leading receiver with four catches or 88 yards and a TD.
Czerniewski – who with ACU's Gale is one of nine finalists for the Harlon Hill Trophy recognizing the top player in NCAA Divsion II – completed 20 of 27 passes for 286 yards and four TDs.