The touchdown capped an 80-yard scoring drive and gave the Aggies (1-2) their first win of the year. The Trojans, coming off of a 24-14 win over 17th-ranked Missouri last week, fall to 2-1. It was Troy University's first-ever Sun Belt Conference game.
After trailing most of the game, Troy had taken an 18-15 lead with 6:58 left to play when Greg Whibbs converted a 34-yard field goal.
Troy had tied the game, 15-15, on the first play of the fourth quarter when quarterback Aaron Leak completed a 33-yard scoring pass to James Earl Cray.
After falling behind 7-3 early on, the Aggies used three field goals by Ryan Guardia and a Pierce touchdown pass to Jeremy Lawson to build a lead.
Pierce completed 22 of 34 passes for 219 yards and two touchdowns to lead the Aggies. Muammar Ali led NMSU in rushing with 50 yards on 18 carries.
Troy used two quarterbacks -- Leak, a senior, and D.T. McDowell, a freshman, shared the duties. Leak completed 10 of 19 passes for 165 yards, while McDowell completed 3 of 4 passes for 18 yards.
DeWhitt Betterson led Troy on the ground with 137 yards on 23 carries. It was Betterson's 1-yard scoring run that gave Troy its only lead of the game, 7-3, in the second quarter.
New Mexico State hosts New Mexico next Saturday, while Troy plays at South Carolina