BOSTON – All season long, the St. Mary’s girls basketball team played knowing that there were expectations for the Spartans to finally get to play for a state championship.On Monday at TD Garden, the Spartans made that dream become a reality.Senior Cassi Amenta led the way with 19 points, including two critical free throws with 3.7 seconds left, to help the Spartans survive a superhuman effort from Coyle & Cassidy’s Brenna Gonsalves, who had 25 points, in a 53-50 St. Mary’s win on the parquet.Click here for a photo gallery.St. Mary’s (23-4) will play either Sutton or Lee on Saturday (10:45 am) at the DCU Center for the Division 3 state title.”This is something we’ve talked about from day one,” St. Mary’s coach Jeff Newhall said. “But to say it and to pull it off is two different things. Everyone in that locker room has had a tremendous season.”Getting to the state final was by no means easy for St. Mary’s on Monday as every time it seemed like it would take a foothold, Gonsalves and the Warriors (22-3) would charge right back. The senior scored 13 of her 25 points in the fourth quarter when she put her team on her back and nearly carried it to a win.”(Gonsalves) is an excellent player,” Amenta said. “It was a real challenge down there for Tori and me to guard her ? but this has been the best season I’ve ever been a part of.”The Spartans seemed to have things well in hand when the fourth quarter began with them holding a 39-27 lead. It was still a comfortable seven-point lead at 40-33 with 5:25 left when things started to go a little haywire for St. Mary’s.Coyle turned up the defensive pressure and Gonsalves hit baskets seconds apart to suddenly cut the gap to 40-37 with an eternity of time remaining.”We haven’t had trouble breaking the press all year and then all of a sudden we started having problems with it,” Newhall said.The Spartans responded in turn as Brianna Rudolph hit two free throws and Tori Faieta’s conventional 3-point play made it 45-37 with 3:29 to go. Coyle didn’t go away though as Missy Perry banked home a three and Gonsalves scored inside to get it back to three again.”Coyle is an excellent team,” Newhall said. “And Brenna is a tremendous player.”Baskets from Kirsten Ferrari and Rudolph in quick succession seemed to finally have the Spartans over the hump but Coyle charged back again as Gonsalves’ layup cut the gap to 49-47 with 30 ticks left.Amenta was fouled and drilled two free throws with 17.4 left to make it 51-47 before Gonsalves hit a three from Brighton to cut it to one at 51-50. Amenta was fouled again and coolly swished both free throws with 3.7 seconds left to finally salt things away.”For Cassi to go 4-for-4 at the line in the Garden with everyone yelling at you says a lot about her,” Newhall said. “We had just enough to get the job done in this game.”St. Mary’s led most of the way, taking a 13-10 lead after one quarter and carrying a 22-19 lead into halftime. The Spartans pushed the lead to nine on Jennie Mucciarone’s runner late in the third before Coyle went about making things quite dramatic.