AIR FORCE ACADEMY, Colo. -- Army's Scott Williams was twisting his way toward the goal line when Air Force defensive back Josh Hall punched the ball out of his arms and out of the back of the end zone for a touchback in the waning seconds of the first half.
"That was a huge play, goodness. Gigantic play," Falcons coach Troy Calhoun said.
It was the kindling for the Falcons' rally from a two-touchdown halftime deficit and a 24-14 win over the Black Knights on Saturday. With the win, Air Force retained the coveted Commander-in-Chief's Trophy.
"That was a gigantic play because he was inches away from going into the end zone and Josh got the ball out and they also had another guy going to get the ball in the back of the end zone and he was just two steps short from getting it," fellow Falcons defensive back Jon Davis said. "That play was huge."
Hall said it sent the Falcons into the locker room with determination instead of dejection.
"I think it was the start of the turnaround," Hall said, "because as a defense we played amazingly the second half. We were having a horrible first half. I felt like it could have been 35-0 easily."
Conversely, the Black Knights headed into halftime kicking themselves.
"We could have gone into the half 28-0, and if we'd have done that, the second half probably would have gone a different way," Army fullback Jared Hassin said. "We need to find that fire in the second half."
After being outgained on the ground by 230 yards in the first half, the Falcons (5-4) outscored the Black Knights 21-0 in a third-quarter blitz that included two field goals, two touchdowns, a two-point conversion and two takeaways.
Parker Herrington kicked a career-high three field goals for the Falcons, who recovered fumbles that allowed them to start drives at the Army 29, 19 and 14 in the second half.
"It was all about penalties, turnovers and missed opportunities," Army coach Rich Ellerson lamented.
Until its meltdown, Army (3-6) looked primed to end its 11-game skid against the service academies and win a share of its first Commander trophy since 1996.
The Falcons were fortunate to only be trailing 14-0 at halftime. Air Force stopped Army on fourth down twice in the red zone. Along with Williams' fumble through the back of the end zone, the Black Knights were denied once at the 1.
Air Force started the second half with a drive that ended in Herrington's 37-yard field goal. After a punt, Jefferson's 2-yard TD run and Asher Clark's 2-point conversion run pulled Air Force to 14-11.
Army quarterback Max Jenkins fumbled the snap on the ensuing drive and that led to Herrington's 39-yard field goal that tied the score at 14.
The Black Knights then bungled a fake punt, and linebacker Stephan Atrice scooped up the ball at the Army 14. Four plays later, Jefferson's 1-yard TD run gave Air Force a 21-14 lead.
"I love the guts they had to fake that punt," Calhoun said.
Early in the fourth quarter, Jon Davis stripped Hassin and returned the fumble to the Army 19. Herrington followed with a 39-yarder that gave the Falcons a 24-14 lead.
Davis, who tied his career high with a dozen tackles, sealed the win with an interception deep in Air Force territory with four minutes left.
"We had little tweaks here and there but I think the biggest change was just our mentality," Falcons linebacker Jordan Waiwaiole said.
The Black Knights have now lost five consecutive road games and their last six games against the Falcons.
Air Force beat Navy 35-34 in overtime last month and won its second straight Commander-in-Chief's Trophy after ending its eight-year drought.
Last season, Jefferson -- who finished his career 6-1 against Army and Navy -- was disappointed to learn only the seniors got to go to the White House to meet President Obama and receive the trophy that signifies superiority among the service academies.
"Me and a couple other guys, we were devastated just because we knew we were such a big factor for the team," Jefferson said. "And I was talking to a couple of people and they told me, 'You have to go out there and earn it again. If you want it that bad, you'll get the job done and you'll punch your own ticket."
Follow AP Sports Writer Arnie Melendrez Stapleton on Twitter: http://twitter.com/arniestapleton