Watanabe scored on her first shot six minutes into the game, and helped O'ahu Interscholastic Association East champion Castle remain undefeated with a 1-0 victory over host Moanalua.

Watanabe, a sophomore forward, knocked in a loose ball after the Moanalua defenders failed to clear a corner kick.

"The ball just popped out," said Watanabe, a two-year starter. "I guess I was lucky."

With the victory, the Knights ended the regular season at 9-0-1 and earned a first-round bye in the OIA playoffs, which start Friday.

The Menehunes finished 6-2-2 and gained a berth in the OIA playoffs. Moanalua would have earned a first-round bye had it defeated Castle yesterday. The top two East Division teams earn first-round byes.

"We had planned to get on top of (Moanalua) right away and try to force a quick score," Castle coach Mark Kane said. "The first team did their job, which was to get us a lead."

On Wednesday, Castle clinched its first OIA East title since 2000, which was also the last time the Knights advanced to the state tournament.

With the title secured, Kane said he used yesterday's game to sharpen his reserve players in the second half.

"I needed to give my bench time to play," Kane said. "They were going to come in the second half, and they were going to come in and save the game for us."

Defensively, the Knights received solid play from goalkeepers Christine Everington in the first half, and Mari Tom in the second. Kane said his team has allowed just three goals all season.

Moanalua coach Joe Rutkowski said he thought his team increased the tempo of the game, but Castle was up to the challenge.

"Our girls have been playing real good (fast-paced) soccer," Rutkowski said. "And we've been playing a lot more physical than we had in the beginning. So I thought we would have been a good matchup for Castle, even though they are the champions."

Reach Brandon Masuoka at bmasuoka@honoluluadvertiser.com or 535-2458.

O'ahu Interscholastic Association

Girls Varsity

• Kailua 5, Farrington 0

Kail: Michele Yoshida, Marisa Yamada, Ona Byers, Ariel Moniz, Hea Kane.

• Roosevelt 2, McKinley 0

Roos: Julie Ajifu, Nani Chock

• Kahuku 13, Kaimuki 0

Kahu: Kahanu Ah Puck 3, Tessi Tolutau 2, Vailima Walker 2, Tiana Ahue 1, Kelly Pao 1, Amy Tuttle 1, Christina Duerdan 1, Karla Tailele 1, Noell Au 1.

• Kalani 0, Kaiser 0

Girls JV

• Castle 1, Moanalua 0

Interscholastic League of Honolulu

• Pac-Five 3, St. Francis 1

P5: Jenna Wong, Ashley Medcalf, Melissa Canite. StF: Jennifer Scelsa.

• Punahou 6, Mid-Pacific 0