Middleton scored a career-high 19 points and fifth-seeded Texas A&M beat No. 12 Utah State 69-53 on Friday in the opening round of the South Regional.
The Aggies (24-9) advanced to the second round for the fifth consecutive year. They will face No. 4 seed Purdue on Sunday.
David Loubeau added 12 points and B.J. Holmes had 11 for Texas A&M, which disrupted Utah State into one of its worst shooting performances of the season and dominated the rebounding.
Utah State (27-8) lost its fifth consecutive first-round game. Its last win came in 2001 over Ohio State. The Aggies shot 38 percent, well below their season average of 49 percent, and scored 20 points below their season average.
Middleton, a 6-foot-7 forward whose previous high was 17 points, did not become a starter until after the team was reconfigured to deal with the horrific broken leg sustained by guard Derrick Roland in late December at Washington. Middleton has been a solid performer, but elevated his play in the Big 12 tournament, averaging 15 points in three games.
Middleton scored 14 points in the first half as Texas A&M used sharp shooting to take 42-29 lead.
Consecutive 3-pointers by Middleton keyed a 10-0 run that gave A&M a 14-5 lead. Middleton, who averages 7.0 points per game, hit another 3 for a 21-13 lead as Utah State made just six of its first 14 shots.
Jaxon Myaer's basket for Utah State cut the A&M lead to three points, but Middleton replied with his fourth 3-pointer and Holmes added two as A&M took a 30-20 lead.
Texas A&M closed with a 10-4 run over the final 4 minutes for a 42-29 halftime lead. They shot 56 percent in the first half, including making 6 of 12 3-point attempts. Utah State shot 41 percent in the first half, and was outrebounded 22-11.
Middleton, rated one of the best high school shooters in the nation at Charleston, S.C., was a 29 percent 3-point shooter coming into the game, but made all four of his attempts in the first.
Utah State hung around in the second half, as Texas A&M cooled off a bit. Nate Bendall's rebound and layup brought the Aggies within 49-42 with 12:33 left.
But Texas A&M scored eight straight points to build a 57-42 lead with 9 minutes left.
Jared Quayle's first field goal since he scored Utah State's first two baskets cut the A&M lead to 57-47. But A&M rattled off eight straight points, capped by Holmes' 3-pointer, for a 65-47 lead with 4 minutes left.
Donald Sloan was the fourth A&M player in double figures with 10. The Aggies shot 49 percent in the game, making 8 of 18 3-point attempts and 11 of 14 free throws.
A team that averages 42 percent from 3-point range, Utah State made just 5 of 20, and missed all four of its free throw attempts. Utah State was 23-0 this season when making at least five 3-pointers.
Quayle, Utah State's all-Western Athletic Conference guard, was 5 of 18 from the field in one of the worst shooting performances of his USU career.
Tai Wesley led Utah State with 14 points, while Quayle scored 11.
Utah State has been to the tournament 19 times, but is 6-21 overall.