After Tech quarterback Sonny Cumbie's 50th and final pass of the afternoon fell incomplete, A&M players stormed the field and the frenzied Kyle Field crowd of 82,278 erupted with cheers. The Red Raiders (6-4, 4-3) watched the wild celebration in stunned silence.
"It was a great football game, I'm really happy for our players and our fans," A&M coach Dennis Franchione said. "Kind of my breath taken away right now."
Lewis finished with 115 yards rushing on 19 carries and Reggie McNeal added 309 yards of total offense and a touchdown in a game that started as a surprising defensive struggle and ended with plenty of offensive fireworks.
The Red Raiders saw a three-game winning streak over their hated in-state rival come to an end in the kind of high-scoring, back-and-forth contest that favored the nation's No. 3 offense.
Both offenses, which came into the game averaging combined 69 points and 952 yards a game, sputtered along for three quarters - A&M held a 12-7 lead - before coming alive in the electrifying fourth.
The Aggies, however, made one more play on offense when it really counted.
A&M fullback Keith Joseph bulled into the end zone from a yard out with 5:38 left, completing a 10-play, 80-yard drive to give the Aggies a 25-18 lead.
But Cumbie methodically directed Tech's spread offense down the field, going 6-of-8 for 50 yards on the final drive of regulation.
His second touchdown of the game went to Jarrett Hicks, who dropped what would have been a sure touchdown in the end zone on the previous drive.
Hicks gave a slight shove to Buhl, and quickly went to the ground to make the tying touchdown catch with 10 seconds left. Tech's sideline erupted while the mostly maroon-clad fans went eerily quiet.
That was the last hurrah for the Red Raiders' vaunted offense, though.
After Lewis' spinning touchdown run on the first play of overtime, Cumbie completed a 1-yard pass to Trey Haverty before throwing three straight incompletions to end the game.
Cumbie finished 31-of-50 for 294 yards with two touchdowns and three interceptions, his least productive game of the season. Taurean Henderson had 131 yards of total offense and two touchdowns and Cody Fuller added seven receptions for 124 yards.
For A&M, the win served as a bit of revenge for a 59-28 rout by Texas Tech last year behind a Big 12-record eight touchdown passes by B.J. Symons. Coming into this game, the Red Raiders had won three straight and seven of the last nine in this simmering rivalry.
More than bragging rights were at stake in this game. A&M might now be the front-runner for a more attractive bowl, with the Cotton Bowl in Dallas the likely prize should No. 6 Texas make it into the Bowl Championship Series.