Costa Mesa High's Aubry Hill, left, competes against Estancia's Valery Medina during an Orange Coast League game on Wednesday. (KEVIN CHANG, Daily Pilot / January 16, 2013)

COSTA MESA — Aubry Hill shined Wednesday for the Costa Mesa High girls' water polo team, but it was her actions from months before that helped ensure the Mustangs would be victorious in the Battle for the Bell.

Hill got more serious about water polo, starting to play club. In last summer's USA Water Polo Junior Olympics, she played for both a 16-and-under and 18-and-under squad.

The senior defender also has continued to build her leg strength.

The Mustangs certainly looked strong against rival Estancia.

Hill excelled on both ends of the pool and senior Kellie Thorsness scored eight goals as Costa Mesa routed Estancia, 20-4, at the Eagles' pool.

Costa Mesa (13-8, 1-1 in the Orange Coast League) has never lost to Estancia (11-9, 0-1) in girls' water polo. But at times through the years, the games have been close. Last year, Mesa edged Estancia, 7-6, in the bell game.

"I didn't stop polo during the summer," Hill said. "We all knew that being that close could not happen again this year. It just couldn't happen."

Hill helped make sure the margin was larger this time. She had four goals and drew three exclusions and a penalty shot for the Mustangs.

On the defensive end, it was her work on Estancia senior Ilene Umansky that also was key. Umansky, who came into the game second in Orange County with 87 goals scored, tied a season-low with two goals Wednesday.

One of Umansky's scores was spectacular. Late in the second quarter she simply flung the ball into the net from more than half-tank. That strike, with 11 seconds left before halftime, narrowed Costa Mesa's advantage to 9-4.

But the Mustangs outscored the Eagles, 11-0, in the second half.

"I think that [Umansky] didn't realize how fast we were going to come out swimming," said Hill, who plans to play water polo and swim at Iona College or nearby at Golden West. "I've learned that if you counter their best players, they get tired. I just countered her, we kept countering her until she got tired and just was like, 'I'm not doing it.'

"Also, I've worked really hard these past few years building up my legs. My legs are so much stronger than last year, so it was just kind of easy to push around the pool. I definitely think she got tired. Last year, I remember she didn't get pulled out, and she got pulled out this year to rest. She underestimated us. They all did."

Thorsness matched a season-high with her eight goals, and senior Alicia Rederscheid added six goals, three on penalty shots.

Coach Tim Postiff said it was Rederscheid's best game of the season. Costa Mesa also converted all five of its power-play opportunities.

"We're definitely a lot better than we were last year," said Thorsness, who also drew a five-meter and had two field blocks. "We've just been working harder, I guess. We have [morning practices] two to three times a week. Girls are stepping up to the plate."

Senior Ashley Tfaye and sophomore Lauren Smith also scored for Mesa, and Smith dished out three assists. Junior goalie Kaitlyn Hill, Aubry's younger sister, made 10 saves.

Postiff said his team has been playing well since a trip up north to the Arroyo Grande tournament earlier this month. Costa Mesa went 4-1 at the tournament, only losing to host Arroyo Grande.

"I think it's a good experience for them to go up and play, to do things other than water polo," Postiff said. "I think Thursday was really helpful. We drove up in the van together, and they went to Hearst Castle, we went to dinner together. They spent an entire day together, instead of being separated when they're at school and in classes. It led to a great weekend, and that's continued on."

Postiff said he was pleased with his team's defensive effort in Wednesday's match, as it led to easy offense. Aubry Hill, Kaitlyn Hill, Rederscheid and Thorsness all had a pair of steals for the Mustangs.

Umansky did lead Estancia with her two goals, and juniors Abby Garcia and Nikkie Blinn also scored. Blinn, a set defender, had three steals, and senior goalie Alexis Paul had four saves and also made four steals.

But Estancia Coach Jennifer Broderick saw her team struggle as Costa Mesa focused its attention on Umansky.

"They definitely knew to look for Ilene as our scoring threat," Broderick said. "I thought that we could have done a better job of moving the scoring around, so different people had opportunities. We just didn't do that as well as we have in other games ... We didn't have as much speed as they had. We definitely didn't play to our best level today."

With Wednesday's result, the Mustangs again have established themselves as strong contenders for second place in league. They play Godinez on Jan. 23 at Santa Ana Valley High, while Estancia plays host to six-time defending league champion Laguna Beach on the same day.

Thorsness said she has talked to Pitzer College, Cal Lutheran and University of La Verne. As for the rest of her final high school season, she said the Mustangs are confident.

"[The Arroyo Grande tournament] just really showed us how well we can do against really hard teams," she said. "If we put our mind to it we can beat any team, if we try."

matthew.szabo@latimes.com

Twitter: @mjszabo