Groton — More than one observer of high school baseball south of Norwich this spring was suspicious of Killingly High school's gaudy record, reasoning that its quality of competition was, well, lacking quality.

And then came this week — Thursday in particular — when Killingly silenced every mouth that expressed any doubt.

Killingly, which won its first regular season title of any kind since 1973 last week, won the school's first Eastern Connecticut Conference tournament championship, beating Fitch 1-0 in the title game on the Falcons' home turf.

A few hours earlier, third-seeded Killingly won at No. 2 Waterford, too, 13-2, authoring perhaps the greatest day in program history.

"Everybody pretty much picked Waterford to win this," Killingly coach Ben Desaulnier said. "The four teams left (to begin play Thursday) were East Lyme, Fitch, Waterford and us. Those other teams are supposed to be there. It's normal. But it's not normal for us. That's what makes this so special."

Tournament Most Valuable Player (and Mitchell College-bound) Bo Yaworski, who pitched a no-hitter earlier in the tournament and had three hits Thursday night, said, "We could see it all year, where teams thought they were going to steamroll us. But we came ready to win."

Yaworski was involved in the night's only scoring play, doubling home Brady Waterman in the fourth. With the count 1-2, Fitch pitcher Ramiro Zavala threw a breaking ball in the dirt that skipped past catcher Cam McGugan. Waterman took second, but Yaworski thought he was hit by the pitch and went to first.

The umpires decided Yaworski didn't get hit, forcing him to resume the at bat. Result: RBI double.

"I knew when I went back to hit I wasn't in a great count," Yaworski said. "I was just trying to put it in play."

The run was enough for starter Cole Lavigne, who allowed four hits and hit two. Lavigne retired the game's final hitter with the tying run at third.

"At the beginning of the season, we told coach Marcoux (athletic director Kevin Marcoux) that we wanted to play as close to a normal schedule as we could," Desaulnier said (Killingly is 20-2). "We got 14 or 15 games, but we ended up playing 19. Some weeks, we'd do Tuesday, Thursday and a doubleheader Saturday. I think that prepared us for a day like this."

Fitch (15-5), the No. 5 seed advanced to the finals with a 7-1 win over No. 9 East Lyme in the semifinals.

"It definitely stings," Fitch coach Brian McGugan said. "I told the kids that nine straight wins (to eventually win the state championship in two weeks) is hard. The last two times Fitch won a state championship (2005, 2012) we lost the ECC title game. So, it's not the end of the world. And congrats to Killingly. They really played well."

• In the semifinals, Jack Ballou scattered four hits and struck out seven over 5.1 innings during the Falcons' win over No. 9 East Lyme. Ryan O'Connor hit a solo homer, Alex DelCampo was 2-for-3 and Anthony Franco added a double for Fitch, while Carter Chambers had two hits for the Vikings (10-7), including a double. And at Waterford, junior Jay Grzysiewicz pitched a complete game for Killingly against the No. 2 Lancers (16-2), who led 2-1 before Killingly scored six runs in the fifth to break the game open. Connor Podeszwa was 3-for-4 with two doubles and an RBI for Waterford while Will Rocchetti was 3-for-4.

m.dimauro@theday.com