The win was A&M's 19th in a row at home.
Oklahoma (11-8, 3-4 Big 12) cut the lead to two twice in the second half. The second time, a pair of free throws by Nate Carter made it 53-51 with about five minutes left, but A&M (17-3, 5-1) answered with a quick jumper by Dominique Kirk.
Then Law took over. He made three free throws and a basket before dazzling the crowd with an off-balance layup that drew a foul. He hit that free throw and added two more to stretch the lead to 65-53. Law added a pair of free throws with 52 seconds remaining.
The Aggies were down by one at halftime but outscored Oklahoma 7-2 in the opening minutes of the second half to take a 35-31 lead and never trailed again.
The Sooners shot only 34 percent, but stayed in the game by making 19 of 21 free throws. Nate Carter led the Sooners with 19 points and made all 13 of his free throws.
It was A&M's first win over Oklahoma since 1998 and just its second in the 27-game series.
NO. 5 OHIO STATE 66, MICHIGAN STATE 64
In Columbus, Ohio, Greg Oden scored 19 points and Ohio State nearly blew a 20-point halftime lead before holding off Michigan State.
Maurice Josephs' 3-pointer with just over a second left bounced off the rim, preserving the win for the Buckeyes (18-3, 6-1 Big Ten), who won their fifth in a row overall and 21st in a row at home.
They also ended Michigan State's four-game winning streak in Columbus.
NO. 9 PITTSBURGH 72, ST. JOHN'S 46
In Pittsburgh, the Panthers relied on the inside play of Aaron Gray and Sam Young to control poor-shooting St. John's at both ends of the floor, and Pittsburgh extended its best Big East start.
The 7-foot Gray had 13 points and 10 rebounds as Pitt (19-3, 7-1 in Big East) repeatedly limited St. John's (12-9, 3-5) to one shot on offense, preventing the Red Storm from settling into a rhythm. Pitt won its ninth in 10 games.
NO. 11 MEMPHIS 67, SOUTHERN MISSISSIPPI 64
In Memphis, Tenn., Chris Douglas-Roberts scored 15 points, including five in the final 2:28 as Memphis rallied past Southern Mississippi for its ninth-consecutive win.
The Tigers (17-3, 7-0 Conference USA) had to come back from six points down with 6:25 to play. Jeremy Hunt led Memphis with 21 points, and Douglas-Roberts' two free throws with 7.6 seconds left preserved the win.
NO. 13 OKLAHOMA STATE 62, IOWA STATE 50
In Stillwater, Okla., Terrel Harris matched his career high with 21 points on the six-year anniversary of the plane crash that killed 10 men connected to Oklahoma State's basketball program.
For the first time since the crash, the Cowboys (18-3, 4-2 Big 12) played on Jan. 27. The Cowboys extended their winning streak at Gallagher-Iba Arena to 16 games and snapped a three-game home losing streak to teams from the conference's North Division.
NO. 14 BUTLER 68, DETROIT 58
In Detroit, A.J. Graves had 15 points and five assists to help Butler overcome a sluggish second half and beat Detroit for its fifth consecutive victory.
The win kept the Bulldogs (19-2, 7-1 Horizon League) alone in first place in the conference.
BRIGHAM YOUNG 61, NO. 16 AIR FORCE 52
In Provo, Utah, Keena Young scored 17 points, including a three-point play with 19 seconds left as Brigham Young beat Air Force to extend the Cougars' home winning streak to 27.
Trent Plaisted scored 22 points and pulled down seven rebounds for the Cougars (15-2, 5-2 Mountain West), who outrebounded the Falcons 42-20. BYU hasn't lost in the Marriott Center since the season opener in 2005.
NO. 18 NEVADA 79, UTAH STATE 62
In Reno, Nev., Nick Fazekas had 24 points and 18 rebounds and Nevada went on a 10-0 run late in the game to beat Utah State.
Marcelus Kemp added 15 points, Ramon Sessions 13 and Kyle Shiloh 10 for the Wolf Pack (19-2, 7-1 Western Athletic Conference), who have won 12 of their past 13. They are now 56-6 at home since the start of the 2003-04 season.
NO. 22 NOTRE DAME 66, VILLANOVA 63
In South Bend, Ind., Colin Falls scored 23 points, including four in the final 65 seconds, to lead Notre Dame to a victory over Villanova as the Fighting Irish improved to 15-0 at home this season.
Villanova (14-6, 3-4 Big East) had two chances to tie it in the final 18 seconds, but Reggie Redding missed an open 3-pointer and Curtis Sumpter also missed a 3. Sumpter threw up a length-of-the-court shot at the buzzer that was short and wide.
NO. 23 INDIANA 76, MICHIGAN 61
In Bloomington, Ind., Roderick Wilmont and D.J. White scored 15 points apiece as Indiana beat Michigan for the Hoosiers' 11th consecutive victory over the Wolverines and their 13th win in a row at home.
The Hoosiers (15-5, 5-2 Big Ten) were coming off a season-low 43 points in a loss at Illinois, but took control early with their 3-point shooting.
NO. 25 SOUTHERN CALIFORNIA 76, CALIFORNIA 73
In Berkeley, Calif., Daniel Hackett hit a tiebreaking layup with 16 seconds remaining as Southern California hung on after blowing a 17-point lead to beat California.