NORTHAMPTON — He may have just wrapped up his freshman year of high school, but Aiden Keeling-Lococo showed maturity beyond his years on Monday evening.

The Northampton Post 28 center fielder stepped to the plate in the bottom of the seventh inning with the game tied at five and Matthew Walko standing on second base. A base hit would lift his team to 3-0 on the season.

Keeling-Lococo reached base each of his previous four plate appearances, and he timed up Easthampton Post 224 pitcher Will Hogan’s breaking ball and sent it down the right field line. Walko cruised home to give Post 28 a 6-5 walk-off win over Post 224 in an American Legion Senior Division contest at Arcanum Field.

“He threw me three out of four curveballs my last at-bat, so I was sitting curveball,” Keeling-Lococo said. “I saw it out of his hands, and I put the barrel on the ball and hoped everything else went well. It was kind of outside, so I just tried to go the other way with it and keep it in play.”

As he rounded first and saw Walko come to the plate, Keeling-Lococo – who recorded his first career walk-off hit – tossed his helmet in the air soon followed by a mobbing from his teammates.

“He’s a freshman in high school, but he carries himself with a lot of maturity,” Post 28 head coach Adam Krol said of Keeling-Lococo. “Even in a two-strike count, he stays calm and cool. There’s nobody better in that situation, so I was very excited when he came up to the plate. He’s a great player, and that’s why he’s in our lead-off spot.”

Easthampton threatened to hand Northampton its first defeat of the young summer. Post 224 scored the game’s first three runs, and held a slim 3-2 lead through four innings while Post 28 struggled to bring runners in from scoring position.

To kick things off in the top of the first inning, Brendan Capshaw reached on an infield single. Two batters later, Hogan walked. Mikey Thompson then crushed a double in the right-center gap to score both runners and give Easthampton the exact start it was looking for.

Seeing how evenly played Monday’s contest was didn’t surprise Easthampton head coach Erik Fickett one bit considering he and Krol played baseball together for six years.

“They’re a good team, and I played baseball with Adam for a long time, so we know how each other operates,” Fickett said. “I expected it to be this kind of game, but overall they were the better team today.”

Connor Capshaw scored on a Hogan sacrifice fly to make it 3-0 in the top of the third before Northampton scraped two across in the bottom half of the frame to get on the board.

James Lavallee led off with a single followed by a Liam Flynn free pass. Both runners moved over on a passed ball. Next up was Trey Kuzmeski, who launched a fly ball into center field that ended up caught, but was plenty deep enough to plate Lavallee and move Flynn over to third. Elijah Rubinstein grounded one to short to bring in Flynn and put Post 28 within one.

Easthampton extended its lead to 4-2 in the fifth, but once again Northampton responded the next half-inning. Kuzmeski doubled, Rubinstein singled him in, Walko walked and Post 28 was threatening again. Keeling-Lococo sent a fly ball to short right field, and Easthampton’s second baseman and right fielder had a miscue – allowing both Rubinstein and Walko to come home.

Post 28 led 5-4 – its first lead of the game.

“We just kept going,” Krol said. “Even when we fail – we get knocked down – we keep coming. That’s what our guys do. Even though we left 11 runners on base, we scored enough to win. That’s how we look at it. This team is great at just finding a way to win, and that’s gonna help us go a long way this season.”

Despite facing their first deficit of the game, Easthampton didn’t go away. Zach Phakos was hit by a pitch with two outs in the sixth inning, and worked his way all the way around the bases to score. Phakos took second on a passed ball, stole third and came home on another passed ball to tie it up with a strong individual effort.

Fickett said he enjoyed watching his Post 224 team fight back in the game.

It ultimately wasn’t enough, as Keeling-Lococo delivered in the clutch in the very next frame.

“We’re getting out of that rut now, and today was the best baseball we’ve played this year,” Fickett said. “We know how everybody plays now, we’re developing that connection, and it showed today when we were ahead for most of the game. We tied it up at the end, but [Northampton is] a good team and found a way to win.”

Easthampton’s (0-3) next game is Wednesday at home against Longmeadow at 5:45 p.m., while Northampton (3-0) is back in action on Tuesday at Belchertown Post 239 – also at 5:45 p.m.