Thomas' lay-up capped a 7-1 Maryland run in the final 1:11, as they rallied back from being down 66-60. Laurin Mincy started the run with a three-pointer, which Anjale Barrett followed with a fast-break lay-up moments later.
After each side missed a shot in the ensuing seconds, the Terps, down one, were forced to foul to stop the clock, and sent Brittany Rountree of UNC to the line with 12 seconds left. Rountree hit one of two to put the Tar Heels up 67-65, and Maryland promptly called a time-out.
North Carolina only had four team fouls, so Tierra Ruffin-Pratt fouled the Terps twice to tick away seconds off the clock. It left Maryland with an in-bounds play with three seconds left, still down by two. That was when Alyssa Thomas scored her game-tying lay-up right before time expired, giving her team five overtime minutes to try and win the game.
In overtime, both teams went scoreless for a minute and a half before Mincy hit a jumper to put Maryland up two. But Chay Shegog hit a free throw and a jumper and Candace Wood later hit two free throws to put the Tar Heels up by three with two minutes to play.
The turning point came when Thomas nailed a jumper while getting fouled. She missed the free throw, but Tianna Hawkins grabbed the rebound and laid it up for two, putting the Terps ahead by one. They would not relinquish their lead, making crucial free throws to ice the game, 78-72.
Maryland had built up a 36-30 halftime lead, thanks to 14 points by Thomas. But North Carolina came out strong in the second half, tying the game on a jumper by Shegog with 17:28 to go. The teams then battled for the lead over the next several minutes until the Tar Heels finally broke through when Ruffin-Pratt hit a jumper with 6:34 left to go up 61-55.
The Terrapins would cut the deficit to two when Lynetta Kizer sank a three-pointer with three and a half minutes left, but four straight points by Ruffin-Pratt would give UNC the 66-60 lead that set up Maryland's comeback in the final minute and a half.
Thomas finished with a game-high 24 points and eight rebounds. Barrett added 16 with nine assists, Mincy scored 12, and Kizer had 10. Alicia DeVaughn and Tianna Hawkins combined for 22 rebounds, helping the Terrapins out-rebound the Tar Heels, 54-to-44.
Turnovers were a problem all game for Maryland, as they committed 22, eight of which belonged to Barrett. Both teams struggled from the free-throw line; the Terps shot 65.2% from the line, while UNC made just 61.5% of their free throws.
After playing two games in three days, Maryland will now get a three-day break before traveling to taking on No. 12/13 Miami on Thursday night. It will be the first time all season Maryland has faced ranked teams in back-to-back games.