Cary Nadel tried going into the FCIAC quarterfinals with confidence.

After all, the head coach of the Trumbull High softball team saw his players put together one of the finest regular seasons since the last time the Eagles won the conference title in 2010.

But Nadel’s excitement was tempered by experience. Nadel spent a few seasons coaching Darien High standout Erika Osherow during the summer at the 12-U and 14-U levels with the Ridgefield Rebels, so he knows how dominant she can be. He knows how easily Osherow — the FCIAC’s top player — can turn a team’s dream into an unmitigated nightmare.

“When you’re playing against a kid you’ve coached, you have to try and know what their weaknesses are,” Nadel said. “And she doesn’t have many.”

Osherow proved that once again, tossing a complete-game three-hitter while taking part in an offense that produced 15 hits off two Trumbull pitchers to lead second-seeded Darien to a 12-1 victory over No. 7 Trumbull Saturday afternoon.

Trumbull (15-6 overall), which has now dropped six straight against Darien, scratched out a run against Osherow to take a 1-0 lead in the top of the second after a leadoff walk by senior Emily Clark and a one-out, RBI-double by sophomore shortstop Taylor Brown.

But the senior right-hander was nearly unhittable after that, allowing just three other base-runners on a walk to Erica Fluskey, a fifth-inning single by Jayme Thompson and a single by Fluskey in the sixth.

“You always want to beat your old coach,” said Nadel, whose team lost to Darien 6-2 during the regular season. “Same thing with the Trumbull girls when I coach against them during the summer with Ridgefield. I’m going to want to beat them and they’re going to want to beat me.”

That’s what made this game so much fun for Osherow, whose team lost in the FCIAC championship against St. Joseph last year after winning titles in 2011 and 2012.

“It’s definitely a fun matchup just because I know the girls and he knows me,” Osherow said. “It definitely makes it more interesting.”

Osherow is probably tougher against teams like Trumbull because she knows she has to be sharp against an opposing coach who knows her inside and out.

“I try to approach every team the same, but knowing that Cary knows me and I know him, it makes it fun,” she said. “He knows what I can do and what I can’t do, so I try to mix it up sometimes. I try to see what he really does know about me.”

Nadel tried to pitch around Osherow.

“If you don’t she’ll crush it,” he said. “She’s the strongest player on the field.”

Nadel had his players hitting off pitching machines throwing 65 miles-per-hour leading up to the game, but neither tactic worked.

Osherow struck out seven and went 2-for-3 with a walk and two runs scored. And it wasn’t even Osherow doing most of the damage.

The Blue Wave exploded for five runs in the second, all of which came with two outs, including an RBI-single by Sophia Barbour (3-for-3, two doubles) and a three-run triple by Kelly Vodola (3-for-3, four RBIs).

Darien (19-2) added one in the third on a solo home run by Cassie Lopiano, one in the fourth and blew the game wide open with five more in the sixth.

“They were all clean hits. You can’t do much about clean hits,” Nadel said. “They earned the win. We didn’t give it to them. We only made one error and had one mental lapse, so maybe you can take two runs off the board.

“They’re a good team and I wish them all the luck in the world going forward.”

Trumbull moves onto the Class LL state tournament where it will likely be a No. 9 seed and enjoy at least one home game. The Eagles could end up facing Darien once again.

“The game plan is to have two or three home games,” Nadel said. “Our goal is to make it to (Stratford’s) DeLuca Field. There’s no reason why this team can’t get three home games out of states.”