Reed scored from a yard out midway through the quarter and Buchanan punched it in from the 10 with 1:15 left to give the Black Knights (2-1) a 14-0 lead.
Robert Henry had a 19-yard touchdown run early in the second quarter to get the Roadrunners (1-2) on the scoreboard. Quinn Maretzki followed with 23- and 45-yard field goals to push Army's lead to 20-7. Eddie Lee Marburger connected with Tykee Ogle-Kellogg for a 46-yard touchdown on the final play of the quarter to pull UTSA within 20-14 at halftime.
Maretzki added a third field goal, but Marburger hooked up with Joshua Cephus for a 44-yard score and the Roadrunners trailed 23-21 with 7:04 left in the third quarter. It took the Black Knights just two plays — a 55-yard completion from running back Markel Johnson to Isaiah Alston and a 25-yard scoring strike from Bryson Daily to Noah Short — to retake a two-score lead.
Daily scored on a 3-yard run with 6:45 left to play, but Marburger connected with Devin McCuin for a 72-yard score and the pair teamed up again for the two-point conversion to get the Roadrunners within 37-29 just 33 seconds later. The UTSA defense forced a three-and-out and Army's defense did likewise. Daily twice ran for first downs in the final three minutes to wrap up the victory.
Daily completed 7 of 17 passes for 133 yards. Reed rushed 20 times for 107 yards, while Daily added 100 on 24 carries.
Marburger, a sophomore, got the start at quarterback for the Roadrunners in place of senior Frank Harris, who is out with an injured toe. He completed 17 of 25 passes for 239 yards.
AP college football: https://apnews.com/hub/college-football and https://apnews.com/hub/ap-top-25-college-football-poll