BILLERICA – If St. Mary’s was looking for a test heading into the meat of its Division 3 North tournament run, the Spartans got it Saturday when the Shawsheen softball team gave them all they could handle.The Spartans’ 3-2 win – triggered by a sixth-inning two-run homer by catcher Erin McAndrews – puts them into the quarterfinals Tuesday (4) at Ipswich.”This has to be the best first-round game – ever – in the history of first-round games,” said a happy St. Mary’s coach Colleen Newbury afterward. “For a 3-2 game, there’s a lot to talk about.”For a while, it looked like this would be a typical St. Mary’s-Shawsheen matchup. The Spartans and Rams faced each other in four straight Division 3 North finals between 2001 and 2004, with Shawsheen winning three, a couple of them in most frustrating fashion. This one looked to be like just one more as Shawsheen clung to a 2-1 lead into the sixth, with time running out for St. Mary’s.However, Maria Nazzaro, leading off the sixth, did something on which she’d been working diligently the second half of the season: she bunted her way on. Next came McAndrews.”It was supposed to be a hit-and-run,” said McAndrews. “Maria did her part, getting on base, and that was awesome.”But I swung,” McAndrews said, “and it happened to go out.”She swung at the first pitch, actually, and it took off on a line, clearing the right field fence, and giving St. Mary’s a 3-2 lead.From there, St. Mary’s simply hung on for dear life. Sam Kiley, pitching in relief of starter Vanessa LaFauci, had a couple of tough innings, but came through it unscathed. In the sixth, Brooke Mallahan reached on a single to left, stole second, and went to third on a groundout by the dangerous Jenna Zechner, whose solo homer in the fourth had given Shawsheen the lead.Kiley fanned pinch-hitter Sara Elwell and then, after an agonizingly long at-bat, walked pitcher Kelli Jo Deardorff. But Kiley bore down, and got Kristina Lees to hit a popup to third that caught just enough of the wind to make it a circus catch for Jenna Fraher, who had to lean back to snatch it out of the sky.In the top of the seventh, St. Mary’s almost picked up an insurance run when Gabriella Cohan led off with a double. Fraher sacrificed her to third, but she couldn’t get any farther, even though Kristina Burri’s two-out drive to left sent Amanda Russo all the way to the fence to make the play.Shawsheen was at it again in the bottom of the seventh, with Francesca Pesantes leading off by ripping one off Fraher’s glove for a single. Makayla DiMauro sacrificed her to second, with Burri making the putout. However, Pesantes strayed too far off second and Burri fired to Kristen Mondello, who was standing on the bag. A furious rundown ensued, with McAndrews getting involved in running Pesantes back to second before throwing to Burri, who then chased her back to third and made the tag.”Everybody got involved in that one,” Newbury said. “I hope you noticed that even the outfielders came in to back up bases. We work on that a lot.”That was Shawsheen’s last gasp, as Russo fouled a two-strike bunt attempt off to end the game.”Our pitching was superb,” Newbury said. “We started LaFauci because we figured she’d keep hitters off balance, and that’s what happened. They only hit one ball hard – the home run.”Both St. Mary’s and Shawsheen scored their other runs on wild pitches.