For Tonianne Larson, it was just like a day at the beach.

Larson had been preparing for this moment since elementary school, when she and many of her current teammates first started playing whiffle ball together on the beach.

“We all knew each other, this is obviously a small town,” said Larson, the ace of the Long Beach softball team. “We all went to different elementary schools. But we all went to the same beach.”

Now, instead of playing on sand, they play on dirt. Instead of being surrounded by the ocean, they’re surrounded by grass. And on Saturday, the longtime teammates earned their biggest win yet as Long Beach defeated defending county champion Oceanside, 2-0, in the Nassau Class AA quarterfinals.

Larson tossed a two-hit shutout and also delivered a go-ahead RBI double in the bottom of the sixth inning.

“Toni is the hardest worker on the team,” Long Beach coach Carmine Verde said. “She’s a performer. She knows in the big game she has to rise to the occasion. She did that today, both on the mound and at the plate.”

Colleen Mannle led off the bottom of the sixth with a bunt single. Larson then lined a double to the gap in right-center field and Mannle slid home safely to give Long Beach a 1-0 lead.

“I put myself in a good position with the 2-and-1 count, and I really wanted to win,” Larson said. “I had a girl in position to score, so I just really focused and hit it.”

Kirsthie Rodriguez followed with an RBI single up the middle to increase the lead to 2-0. That was all the support needed for Larson, who struck out seven and walked one by mixing her pitches and hitting her spots. Sabrina Seeger matched zeroes for most of the game, allowing four hits and three walks, and striking out four for Oceanside (4-15).

The defense behind Larson played flawlessly, a point of emphasis entering the game. Rodriguez made a series of pretty catches in center, including a running grab on a long drive by Grace Bandini in the top of the fourth. Second baseman Jackie Muratori and third baseman Mannle prevented a few base hits in the infield.

advertisement | advertise on newsday

“Stay on your toes and make the plays,” Mannle said of the defensive strategy. “Tonianne pitched a great game and we just had to back her up with all we had . . . Once they got one runner on they were stealing on us. So just keeping them off the bases, that was all we needed so we could get back in the dugout and hit.”

Once they did that, Larson delivered, helping to send Long Beach (11-7) to the best-of-three semifinal series against top-seeded MacArthur, which begins on Monday.

So, did she have any game-winning hits similar to Saturday’s back when they played whiffle ball on the beach all those years ago?

“No,” she said with a laugh. “I wasn’t that good when I was younger.”