Alyssa Ramsey scored two goals and assisted on Maggie Tomecka's for the second-ranked Tar Heels (21-1-4), who have won 16 of 20 NCAA titles and also captured the 1980 AIAW championship.
Carolina could face a rematch with Santa Clara in a semifinal game next Friday. The Broncos, who meet Michigan in a quarterfinal clash on Saturday afternoon, beat the Tar Heels, 1-0, on an Aly Wagner goal in last year's championship game.
Texas A&M managed five shots against North Carolina, a huge improvement over its third-round encounter. The Aggies (18-5-3) reached the quarterfinals for the second straight year by beating UCLA on penalty kicks after a 0-0 draw. They were outshot, 21-0, in that match.
The Tar Heels took charge early, scoring just 22 seconds into the game -- the fastest goal in the team's 79-game NCAA Tournament history. Susan Bush took the ball into the right corner, then fed Lindsay Tarpley just inside the A&M box. The freshman sent the ball to the middle for Anne Morrell, who held off a defender with her back to the goal, then fed Ramsey, who finished from 8 yards.
North Carolina put the result away early in the second half. Tomecka headed home a Ramsey corner kick in the 52nd minute, and Ramsey raced behind the A&M defense for a ball from Morrell, then beat Aggie goalkeeper Kati Jo Spisak in the 54th,
Ramsey's goals were her 16th and 17th of the season.
North Carolina, which struggled to score goals at times this season, has played superb soccer since the start of the Atlantic Coast Conference tournament three weeks ago, outscoring foes, 28-2, over the past seven games.
No. 4 Santa Clara (18-4-1), seeking its eighth final-four appearance and its sixth in seven years, will be home against Michigan (16-5-2) in one of three quarterfinals scheduled for Saturday.
No. 13 Penn State (18-3-1) visits No. 6 Connecticut (21-2-1) and No. 1 Stanford (21-1-0) plays host to No. 7 Portland (17-4-2) on the other side of the bracket.