By Emily Wright, Globe Correspondent

A minute after Missy Perry missed a trey in the fourth quarter of yesterday’s Division 3 South section final at UMass-Boston, the 5-foot, 3-inch junior guard took the same shot from just outside the arc and drained it to give Coyle & Cassidy a 61-60 edge over Archbishop Williams with 1:43 left in the game. Perry’s bomb came on the heels of two Tricia Quinn free throws, and sparked a 12-3 run and gave way to a 70-63 victory.

No. 10 Coyle & Cassidy coach Mike O’Brien had no problem with Perry (13 points, 3 assists, 2 steals, 1 rebound) taking the shot, despite her earlier failed attempt.

“The other night she missed 9 threes, she’s just that kind of a shooter,” O’Brien said. “She’s a scorer, she’s streaky. She takes that shot, and we have no problem taking that shot, ever. If it goes in that’s great. She had missed a whole a bunch, so how much does that say about her guts.”

The Warriors clinched the South section title for the first time in 24 years and are headed to the TD Garden on Monday at 4:15 to face St. Mary’s in the MIAA Division 3 state semifinals.

The fourth quarter battle was led by senior Brenna Gonsalves (32 points, 6 rebounds, 5 assists) who scored 16 points in 8 minutes, and junior center Tricia Quinn (12 points, 15 rebounds) who single-handedly out-rebounded the Archies 8-5 in the quarter.

After taking a 34-30 halftime lead, the Warriors were outscored 19-6 in the third and trailed by as many as 11 in the same quarter. O’Brien attribute’s the 50 percent shooting in the fourth quarter to a mentally tough squad that was ready for a challenge.

“At the end of the third quarter we just all talked about keeping our composure and the lead wasn’t that much so we knew what we were capable of doing,” Gonsalves said. “It was just a matter of going out there and playing with heart and playing as best as we possibly could, and everyone stepped up and that’s what got us the win.”

Archbishop Williams was led by sophomore guard Sara Ryan who scored 20, including a 3-pointer in the fourth that put Archies up 59-52 with 4 minutes left. Earlier in the game AB Williams lost top rebounder Kayla Papazian (5 points, 10 rebounds). The junior took an elbow to the head with a minute left in the third quarter and was sidelined with a deep laceration.