The 16-11 lead vanished after a call went against the Eagles. Muñoz couldn't believe the officials missed the call at the net.
"The ball was outside of our block. It hit the net on their side and it came back and they counted it as a block," said Muñoz, who argued with the official near the scorer's table.
With Costa Mesa's Amanda Moore serving strong and dropping one of her match-high 12 kills, Muñoz called for a timeout. He was visibly upset after the Mustangs cut the Eagles' advantage to one.
"Let me deal with it. Let me handle the situation," Muñoz said he told his players during the timeout. "They still need to stay focused and play as hard as they can. Our main focus is we can't let the ball drop on our side of the net. You just got to keep playing."
The Eagles heeded his advice. They returned to the court and turned it on.
Outside hitter Chloe Davis recorded a kill, igniting a 4-0 run to put Estancia ahead, 21-17. Now, it was Costa Mesa Coach Jeff Weihert's turn to call a timeout.
The Mustangs got within two twice, Molly Settles and Kyndall Jack each produced kills down the stretch. But Lauren Peterson sealed the third set for Estancia with a kill in the back row.
Peterson, an outside hitter and middle blocker, finished with five kills and middle blocker Gianna Jason contributed six kills. Davis totaled five kills.
The Eagles spread the ball around with the help of setter Ilene Umansky, who finished with 16 assists.
"Estancia just played a lot better," Weihert said. "We'll come back and we'll play them in a couple of weeks. We'll definitely be improved.
"We'll just clean up our mess. We'll take care of ourselves. We'll come back and take care of business."
This marked the first meeting between the two programs since last November's match, which decided which team finished third in league and advanced to the CIF Southern Section Division I-A playoffs.
The Eagles won in five at Costa Mesa back then. They had outside hitter Lily McLendon, a first-team all-league selection. She's gone, but Estancia showed it could beat the Mustangs without her.