WORCESTER -- John Frates came to the plate knowing he was going to swing at the first pitch.
With two outs in the bottom of the sixth inning, Frates launched a fastball into the gap in right-center field, scoring two of his Wellesley South teammates to beat Acton-Boxboro for the state championship, 4-3.
"I was thinking I should get on him early and see what I could do with the first pitch," said Frates, still sporting his batting helmet well after the team's victory lap around Joe Schwartz Field.
"When I first hit it, I thought they were going to catch it."
Derrald Webb started the final-inning rally for Wellesley South with a double down the right field line. Catcher TJ Maley represented the game-winning run when he was hit by a pitch from A-B starter Jake McOsker. After McOsker reached his pitch-count limit, he was lifted for Braden Karess to face Frates.
Maley, whose coaches call him the fastest player in Wellesley, smiled a smile full of braces as he reveled in the moments after his game-winning sprint home from first base.
"This is the greatest feeling in the world," he said.
Maley also hit a home run in the second inning to tie the score at 1-1.
McOsker finished the game with nine strikeouts on 88 pitches over 5.2 innings.
Webb, Will Horblit and 11-year-old lefty Henry Weycker combined to allow just one earned run for Wellesley South.
As state champions, Wellesley South will play its first game in the New England Regional in Bristol, Conn. on Saturday against the representative from Maine.