SOUTH DEERFIELD — Frontier’s stay in the MIAA state baseball tournament proved all too brief and unfulfilling, as Blue Hills Regional Tech of Canton came into Valiton Field Monday and walked out with a mild-upset 5-3 victory over the Redhawks in the Division 4 Round of 32.

The Redhawks finished their year at 16-5 after pulling a No. 14 seed in the Division 4 bracket. That followed a share of the Suburban League East championship and their push into the PVIAC Western Mass. Class B semifinals, with a loss to eventual champion Pittsfield.

“We’re working hard from that third Monday in March, long practices, practice on the weekend. These guys put in their time,” said Frontier coach Chris Williams. “It’s definitely a disappointing day, and extra hard for our seniors.”

Blue Hills, the No. 19 seed, put up four runs in the top of the second inning, then weathered Frontier’s comeback in the home second to pull within a run. The score remained 4-3 until the Warriors padded their lead in the top of the fifth, and pitcher Mike McDonagh did the rest.

McDonagh retired 16 of the last 18 Frontier batters he faced. Both runners who reached made it as far as third base, but no closer. In all, the senior right-hander allowed six hits with a walk and eight strikeouts in his complete-game effort.

“That kid threw a gem for them. He was pounding the zone, we weren’t barreling him up, and he kept our hitters off balance well,” Williams said.

The Frontier pitching group of Carter Miller, Joey Hutkoski, and Jack Cusson combined on a six-hitter of their own with six total strikeouts, but also walked four and hit a pair of batters.

Frontier pulled off a gold-star defensive play immediately in the top of the first inning when Gio Poillucci led off with a single and Kevin Farmer bunted into a 2-3 double play, with catcher Henry Drinker catching the popup and firing down to first to double off Poillucci. The Redhawks got a two-out single from Braiden Dion in their half of the first but left him aboard.

Against Frontier starter Miller, Bryan Prioli led off the Warriors’ second with a walk and McDonagh reached when his ground ball was thrown wide of second on an attempted force play. Tom Willard drew a walk to fill the bases, with Rocco Moscaritolo going in to pinch run, and Miller hit Ricky Farry with a pitch to force in Prioli with the game’s first run.

Cam Brown then singled through the hole into left field to score McDonagh. Miller got Seamus Bowles to line to short for the first out, but Poillucci reached on a fielder’s choice grounder with Moscaritolo scoring. Farmer then dropped an RBI single into left field, as Farry crossed for a 4-0 Blue Hills edge.

Right away, Frontier responded when Austin D’Urso drew a walk and Miller reached on an infield single. Shawn Baumann bunted the runners along to second and third and Noah Poreda attempted a bunt of his own, but popped it up to McDonagh in front of the mound. Ninth hitter Grayson Bishop then came up with a worm-burner single straight up the middle, good for two runs, and Bishop moved up to second on the throw home. Cusson then singled inside the third-base bag to bring in Bishop, before McDonagh recorded a strikeout to get out of the inning.

“A ton of credit to our No. 9 hitter (Bishop) for driving in those two runs, Jack Cusson comes up and makes it a ballgame driving in Bishop,” Williams said. “That kind of stopped the bleeding and put us in a spot where we’re feeling good that we can make the comeback. The guys fought the whole time, I’ve got to give them credit.”

After the three-run uprising, McDonagh steadied matters by setting down seven straight Redhawks.

Miller came off the mound with two out in the third and Hutkoski replaced him for Frontier. He retired five straight hitters before the Warriors put up the vital insurance run with one out in the fifth. Farmer shot a double into the right-center field gap, moved to third on Tyler Neville’s fly ball to right, and scored on a wild pitch to make it 5-3.

Frontier got a leadoff single from Bishop in the home fifth, followed by a steal of second and a sacrifice by Brady Poreda to put Bishop at third. McDonagh induced a groundout by Dion to end the threat. The Redhawks managed only one more baserunner on an infield hit by D’Urso with one out in the sixth. Pinch runner Cody Dubreuil stole second and moved to third on Miller’s groundout, but McDonagh got Baumann on a fly ball to left. McDonagh then set down the Redhawks on three straight ground balls in the seventh to close out the win.

Blue Hills (17-5) advances to a Round of 16 game Thursday at No. 3 seed Dennis-Yarmouth (16-7).

Frontier loses seniors Brady Poreda, D’Urso, Miller and Baumann.

“These seniors learned it from the guys ahead of them. I’m thankful for their leadership and for setting the tone,” Williams said. “I’m very impressed with how they’ve worked, and that’s something that sticks. Young guys see that, they know what it takes, and they know what the expectations are. This team got along the whole time, our practices were fun, our games were fun, and we’ve got a lot of guys coming back.”