McHargue, who finished with 297 yards passing, ran for another TD for the Owls (5-6, 3-4 Conference USA), who can qualify for a bowl bid by winning at UTEP next week. McHargue connected with Vance McDonald for a 19-yard TD and Donte Moore for a 7-yard score.
Boswell, a semifinalist for the Lou Groza Award for the top college kicker, made field goals from 56, 51, 43, 53 and 28 yards. He missed from 44. The junior has five field goals of 50-plus yards this season and 10 in his career.
Zach Line ran for both touchdowns for the Mustangs (5-6, 4-3), finishing with 94 yards rushing. Darius Johnson caught six passes for 153 yards for SMU, which can qualify for a bowl by beating Tulsa next week.