James Lewis (12) of Costa Mesa scores against Estancia in the Battle for the Bell.

James Lewis (12) of Costa Mesa scores against Estancia in the Battle for the Bell. (Steven Georges / Daily Pilot)

COSTA MESA — "Not in our house" is a term the Costa Mesa High boys' water polo team has used this season.

Now that they actually have a house, members of the Mustangs have done a masterful job protecting it.

They have not lost at home this season. They weren't about to start in the Battle for the Bell rivalry match.

Costa Mesa jumped ahead early and beat rival Estancia, 9-6, in an Orange Coast League match Wednesday at Costa Mesa High, clinching the third and final league spot into the CIF Southern Section Division III playoffs.

It's the Mustangs' first playoff appearance since 2008. Beating a rival to get there was just icing on the cake for Mesa (19-6, 3-2 in league), which eliminated Estancia (9-14, 2-3) from playoff contention.

"I mean, I could say a lot of stuff," said grinning senior Mesa goalie Mitchell Grandia, who had 11 saves and a pair of steals. "It feels great. It's been my goal since freshman year to go to CIF, and to finally beat them? I hadn't had a game in league where we'd beat them yet."

Mesa did so Wednesday when it counted. A fast start helped. Coach Justin Taylor's Mustangs jumped out to a 4-1 lead midway through the second quarter, as senior James Lewis scored on the counterattack off a pass from Grandia.

The victory was definitely sweet to Lewis, whose three goals tied him for match-high honors with Estancia senior Brooks Watkins. In their first full season with their Olympic-sized 50-meter pool, the Mustangs were definitely motivated.

In front of a large and supportive home crowd, they won the bell game for the first time since that 2008 season. It was a much different story from last year, when Estancia blitzed Mesa, 16-2, as the Eagles went on to CIF.

"You play a water polo team that doesn't have a pool to practice in, that's like playing a football team that doesn't have a field to play on," Lewis said. "You kind of know what the result's going to be. Now that we have a pool, that's what the result is."

The Eagles pulled within two goals on three separate occasions in the second half. The last time it was their leading scorer, senior Paul Sugano-Dyson, drawing an exclusion. Sugano-Dyson then scored the goal himself with 6:08 left in the fourth quarter.

But less than a minute later, Costa Mesa junior Quan Nguyen had an answer when he fired an outside shot into the right corner. Lewis scored on a six-on-five with 1:04 left to up the Mustangs' lead to 9-5 before Sugano-Dyson scored at the final buzzer.

Junior Wyatt Ferris scored twice for the Mustangs, who also beat Estancia, 8-6, in the third-place match of the Central Orange County Tournament on Saturday. Seniors Matt Moore and Jamie Sacco added single goals, and junior Quinn Stone also found the back of the net and contributed three steals.

"We've been working our [behinds] off the entire year," Sacco said. "We've been really determined to try to get to playoffs because of the gnarly losses we had last year. We're really stoked on our improvements."

Max Hume also scored for the Eagles, who had junior goalie Garrett Henshied make seven saves. Seniors Derek Andrews and Brody Henshied each had three steals.

Estancia Coach John Carpenter, who had no returning starters from last year's team, said the difference was that Mesa made more of its outside shots. Still, he was happy the Eagles put themselves in a position to nearly make the playoffs.

"Of course we would have loved to have gone to CIF," Carpenter said. "That's kind of the whole pinnacle, but I try to look at the whole season. They've played well, they've played hard, they've never given up. I'm proud of what they did. It's just that today, Mesa executed a little better than we did."

Justin Taylor said his team was eager to show what it could do with a pool again. He's been pushing them hard in practice, having them swim 6,000 yards a day until about a week ago.

"When we didn't have the pool, we were slow," Taylor said. "We needed to get faster. Practices ran extremely long. We ran four-hour practices all season, and it's because we needed that time to condition."

The Mustangs have responded with a very strong season, matching the 19 wins of that 2008 team that advanced to the CIF quarterfinals. This year's team has also been battle-tested. In the Lil' Pickle Sandwich Showdown tournament that Mesa won at its home pool, the Mustangs won two games — against San Juan Hills and the final against Pacifica — in sudden-death overtime.

"It's a testament to how hard they've worked," Taylor said. "It goes to show what these kids are capable of when they're given the same resources as other kids. The last two years they simply didn't have it [with the pool under construction]. We love our brand-new facility, we're so thankful to have it, but it was hard. It was hard for those kids.

"They got short-changed; there was just no way around it. Whenever they were going to build this pool, the varsity kids at that time were going to have to go without. They were in a tough situation, and they wanted to show what they could do when they had the same resources as everyone else … They wanted to come back this year and show Estancia and everyone else what they were capable of."

Costa Mesa plays at Segerstrom on Monday in its regular-season finale.

Defending CIF champion Laguna Beach beat Saddleback, 22-4, on Wednesday to win the league title for the sixth straight year. Saddleback finished second in league.

matthew.szabo@latimes.com

Twitter: @mjszabo