Brittney Coppa assisted on the goal that gave the Tar Heels (18-3) their first national title in the longest title game in tournament history.
"If anything, it shows with a little belief and a lot of hard work, anything can be possible," said Jenny Levy, the only coach the Tar Heels have known in their 18 seasons. "I have some really tough kids I've worked hard with all season. We've had to build from the ground up. There was no lacrosse in the state of North Carolina when we started our program."
Katie Schwarzmann and Taylor Cummings each had three goals for the Terps (22-1), who were bidding for their 11th championship in 17 appearances.
"High emotion, high intensity and pretty exciting for fans to watch," Maryland coach Cathy Reese said. "I think this one will go down as one of the most exciting national championship games in the history of our sport."
Both goalies played well in overtime after the teams ended regulation tied at 12. North Carolina's Megan Ward stopped Brooke Griffin from point-blank range early in the third overtime.
"I knew I had to make it because it was sudden death," Ward said.
Coppa took an outlet pass from Ward and raced up the field.
"The ball ended up in my stick and I was just like, 'Go,'" Coppa said. "I knew it felt right and I didn't stop. Sammy Jo popped and was open."
Coppa found Tracy to the left of the cage, and she fired a bounce shot from nine yards out that beat Kasey Howard.
"I let one rip just like in practice," Tracy said. "It literally feels all like a dream. To see that ball go in the back of the net was something I've dreamed about since my dad put a stick in my hand. I could not be happier."
Levy didn't have a play called on the winning tally, instead believing in her players' instincts.
"You have to trust at that point that they're going to make the right choice," she said. "(Tracy's) a great finisher. It was the right play. I just tried not to mess it up. We have a lot of trust in our kids to go make plays, to be bold and go for it."
There was a delay after the goal as Maryland requested the officials check the legality of Tracy's stick. North Carolina players celebrated wildly on the field after the officials ruled the stick legal.
"It's been a journey," Levy said. "Everything is a progression. We've been very strategic with how we've built the program. We've battled every step of the way to get where we are today."
Kara Cannizzaro had four goals and two assists for the Tar Heels, who had lost twice to the Terps earlier this season, including the ACC title game when Maryland won its fifth straight conference title.
"We stayed composed and we had a belief in ourselves that we were going to get the ball into our offensive end and we were going to score," Cannizzaro said. "It was just a belief. We just focused on the little things and the big thing happened."
Cannizzaro, a senior, is elated that the Tar Heels' women's lacrosse program will get to hang a national championship plaque next to the 22 owned by the school's women's soccer program. She also feels there will be more next to this one.
"It's nice we get to put a little plaque up next to our women's soccer team," she said. "I think it's going to propel the program. I have faith that they'll be back and this is the first of many."
Coppa and Aly Messinger added three goals for North Carolina, which lost to Northwestern in 2009 in its only other championship game appearance.
Brooke Griffin had two goals and three assists for Maryland.
"That could have gone either way," Reese said. "Pretty classic of a Maryland-North Carolina matchup. There were opportunities on both ends. There's just happened to fall first."
Neither team scored in first overtime, with both goalies coming up with key saves. North Carolina had two great chances early in the second overtime, but Howard made a pair of strong saves on a free-position attempt by Taylor George and point-blank shot by Messinger.
Maryland erased a three-goal halftime deficit by opening the second half with five straight goals over the first 10:05 to take an 11-9 lead. Coppa's driving shot with 18:23 left stopped the Maryland run, pulling the Tar Heels within 11-10 and ending a 16:23 scoreless drought. Cannizzaro tied it at 11 from close range with 12:44 to play.
Cannizzaro scored again from point-blank range to give North Carolina a 12-11 lead with 9 minutes left in regulation, but Alex Aust tied it at 12 with 3:51 remaining when she scored after coming from behind the net.
Maryland had a chance to win it in regulation, but Schwarzmann lost control as she was going in for a shot in the final 10 seconds.
"It definitely stings right now, but we'll get through this," Cummings said. "We played an amazing game. I love all my teammates. It just didn't fall our way this time. The returners won't forget about this one. It will definitely fuel our fire, but we're just getting over this one right now."