Lanphear turned on a 1-2 offering from Lori Spignola and drove the pitch high down the line in right. The ball curled around the foul pole and landed in the street beyond the right field fence to put the Aggies (8-0) in front.
Senior All-American pitcher Mel Dumezich made the long ball stand up, twice stranding the bases loaded and working around nine UNC hits and stranding 11 base runners to pick up her sixth win of the season.
The Tar Heels (6-5) capitalized on a pair of second-inning infield singles to take the early lead.
Amber Parrish led off the frame with a floater that landed behind a drawn-in Amber Garza at third and moved to second on a sacrifice. Following a single up the middle that put runners at the corners, Elisha Elliott pushed a 1-1 pitch through the right side for the RBI and the game's first run.
UNC loaded the bases on another infield single, but Dumezich battled from behind to strike Amy Nece out looking and induce a soft liner to short off the bat of Erin Satterfield to escape further damage.
Spingola (3-3) suffered the loss, allowing six hits and three runs over six innings of work.
Texas A&M faces Pittsburgh in the Aggies' second game of the afternoon, starting at approximately 5:15 p.m.