Will Wagner got to witness plenty of clutch moments on the baseball diamond growing up.

He got to witness his father — seven-time MLB All-Star Billy Wagner — close out game after game in a career that ended with 422 saves.

But the biggest moment of Sunday’s playoff game at Alumni Field belonged to Will. He hit a walk-off single through the right infield gap in the bottom of the 10th inning, driving in Kevin Welsh to give the Keene Swamp Bats an 11-10 win over the Valley Blue Sox in Game 1 of the Northern Division Finals.

The best-of-three series continues with Game 2 tonight at 6:30 at McKenzie Stadium in Holyoke, Mass., with the Bats hoping to eliminate the two-time defending NECBL champions.

“It feels awesome,” Will Wagner said. “To start the game I was not feeling good at all. I started 0-for-3, made a big error [at second base], but you’ve got to keep your head up in those situations. A big hit could come at any time, and it sure did right there.”

Wagner’s hit put an end to a crazy night that featured eight home runs, five lead changes and one of the craziest double plays ever seen. And Wagner was right in the thick of all of it.

The Bats went into the bottom of the ninth trailing 10-7, after Valley scored twice each in the eighth and ninth innings. But then things started falling apart for the Blue Sox pitchers.

Tyler Hankins started the inning by hitting both Randall Bednar and David Bedgood, then walking Wagner to load the bases with no outs. Jackson Svete took over, but saw his third pitch skip past catcher Natale Monastra, allowing Bednar to score.

Svete went on to throw two more wild pitches, bringing in Bedgood and Wagner, and even though Keene recorded no hits that inning, the game was tied and going to extras.

“That was crazy,” Wagner said. “They were just giving it to us right there.”

It was the Bats’ second multi-run comeback of the night, and the third overall.

Bedgood opened the scoring with a two-run homer to right-center field in the first, but then Valley came back with an all-home run attack.

The Blue Sox hit two home runs in the second — a solo shot to left by Isaac Alexander and a two-run shot to center by Dakota Mulcay — then hit two more in the third — back-to-back solo shots, one to left-center by Richard Constantine and another to left by Alexander — to go up 5-2.

Bedgood chipped into the lead with an RBI double to left-center in the fifth, but Joe Lomuscio led off the seventh with a solo homer to left to put Valley ahead 6-3.

But the Bats showed that no lead was safe in the bottom of the seventh. First, Wagner hit a single to center that drove in Bednar and Bedgood, then two batters later Logan Mathieu hit a two-out moonshot to center to give Keene its first lead since the first inning.

“It doesn’t take a lot to get out of this ball field,” Mathieu said. “I don’t think I’ve had a cheap one here yet, which is kind of making me mad, because I’m not putting it to my use, but getting barrel like that, it’s always something that feels good.”

While the game belonged to the offenses, there were multiple clutch defensive plays as well.

Andrew MacNeil threw out Valley’s Travis Holt at home from left field in the ninth, and Welsh almost single-handedly killed a Blue Sox rally in the seventh.

With no outs and runners on second and third, Wagner fielded a grounder and tossed it to Welsh at second base. Welsh chased down a runner caught between second and third, then snuck in a tag on the lead runner before he could dive back to third.

The final clutch defensive stand came from Cristian Sanchez. Keene’s fourth pitcher of the night, following Zach Messinger (six innings), Michael Bacica (two) and Jonathan Edwards (one), Sanchez took the mound in the 10th and put Valley down in order, earning his first win.

“He’s just coming along. He’s got a great arm,” Keene Manager Gary Calhoun said of Sanchez. “He and Jonathan Edwards have had some command issues, but boy, they’re working so hard and they’re positive, and every time they go out, whatever happens, they come back with the same positive attitude.”

In the bottom half, Welsh drew a walk off a full-count pitch, then two batters later Bedgood — also facing a full count — hit a two-out single to right, setting the stage for Wagner.

“He’s been solid all year,” Calhoun said of Bedgood, who reached base in all six plate appearances and finished with a game-high three runs scored and three RBI. “I’m gonna miss that guy.”

While Calhoun said there were plenty of mistakes in this game and the Bats need to put this one behind them and move forward, the team can’t deny feeling confident after such an exciting victory.

“We can come down from anything and come back,” Wagner said. “We’re a strong group of guys, and I think we’ll have a good chance to win tomorrow.”