Miller's older brother, Jimmy, had the game-winning goal in 2006, when Sage Hill beat Costa Mesa in sudden-death overtime. Since then, the league games have been battles, almost always decided by a single goal.
Last year, it was 5-4, Sage Hill.
Miller made sure Sage Hill came out on top again, after a strong pass in from fellow senior Eric Hallett.
"I was thinking about calling a timeout and I saw Eric Hallett was countering hard," Sage Hill Coach Tom Norton said. "It was just a great counterattack. I think that's [Miller's] favorite shot, the backhander, which is great when it works. He's a great player. I'm glad I didn't call timeout."
Both Costa Mesa (4-8, 0-3 in league) and Sage Hill (2-10, 1-2) have been struggling this year. But Miller, Hallett and freshman Arya Nakhjavani each scored three goals, helping the Lightning eke out the win over their rivals.
A year after winning its first CIF playoff game in school history, Sage Hill has an uphill battle to get back to the CIF playoffs.
But the Lightning are on a modest two-game winning streak after losing their first 10 games.
"It's been a tough year," Miller said, adding the program lost three seniors and three other players who decided not to come back. "Luckily, we've had two freshmen who have been pretty good."
The Mustangs earned an ejection in the closing seconds Wednesday, but couldn't get a shot off after a timeout behind pressure defense from Sage senior Eric Fish.
Costa Mesa, led by junior James Lewis' game-highs seven goals and five steals, finished just one-for-six on the power play.
"Six-on-five has been rough for us this year, but when we have the limited practice time we've had we have to prioritize," Costa Mesa Coach Justin Taylor said. "Now that we have more pool time, that's certainly going to be one of the things we look at."