The ninth-seeded Aggies (14-17) were clutch at the line in the second half, nailing 14 in a row to earn their third straight tourney-opening victory. A&M advances to a quarterfinal matchup with top-seed and third-ranked Kansas on Thursday afternoon (2 p.m., ESPN2).
Eighth-seeded Oklahoma (15-16), trailing almost the entire second half, sliced the lead to 47-45 on Romero Osby's four free throws before Harris connected for his second 3-pointer at the 3:55 mark.
David Loubeau hit a bucket for the Aggies that Sam Grooms answered for the Sooners. Then Middleton's 3-pointer gave A&M a 55-47 lead with 1:42 left.
The Aggies used a 16-4 run through the latter stages of the first half to erase an early deficit and take a 27-22 lead into the locker room.
Trailing 14-9 with just over 9 minutes to play, Middleton converted consecutive buckets to pull A&M within one. Then Elston Turner scored A&M's next 8 points, as the Aggies pushed the lead to as much as seven.
Loubeau and Middleton each had 15 points for A&M, while Elston Turner scored 14 and Ray Turner added 12.
Oklahoma (15-16) got 17 points from Osby and 13 from Grooms.
TEXAS A&M POSTGAME NOTES
- Texas A&M won its third straight Big 12 Championship opening game and has won 5 of its last 7 openers dating back to 2006.
- The Aggies' victory was just their second in a first-round game at the Big 12 Championship ... in 2008, A&M won in the first round before advancing to the semifinals (A&M's victories in 2006, 2010 and 2011 were in the quarterfinals).
- Texas A&M won just its second game at the event as a lower-seeded team (2-12 all time) ... the other victory came in 2008 (quarterfinal win over #3 seed K-State, 63-60).
- A&M improved to 6-15 all-time at the Big 12 Championship, and is 6-6 in the event since 2006.
- The Aggies became the sixth straight 9-seed to advance to the Big 12 quarterfinals.
- A&M shot 88.2 percent from the line (15-of-17), a season best.
- The Aggies set a team Big 12 Championship record at the line, besting the previous mark of 83.3 percent (15-of-17) vs Kansas in 2010.
- Texas A&M's 27-22 halftime lead was its first at the half since Feb. 6 vs Texas.
- The Aggies' 5-point halftime advantage was their second-highest against a Big 12 foe this year (34-17, +17 vs Texas Tech on 1/14).
- A&M opened the first half 4-of-18 from the floor (22%), but closed by making 8 of its final 14 shots (57%).
- Texas A&M's 9-board margin on the glass (37-28) was its second highest of the season against a Big 12 opponent (+18 in win at Texas Tech).
- With 15 points, David Loubeau eclipsed the 1,200-point plateau ... Loubeau now has 1,207 for his career, ranking him 19th all-time.
- Loubeau played in his 132nd game at A&M, tying him for fourth on the all-time Aggie list with Dominique Kirk.
- Elston Turner hit two 3-pointers to bring his season total to 70 ... he becomes the fifth player in school history to hit at least 70 treys in a season (Josh Carter 3 times, Bernard King, Derrick Hart, Antoine Wright) ... Turner's total ranks sixth on the school's all-time single-season chart.
- David Loubeau grabbed a season-high 9 rebounds.