Williamsport, which has won 51 of the 58 games it has played this season, advances to challenge for its first state title in three years when it meets Poolesville or Loch Raven on Saturday at 2:30 p.m. at CCBC-Catonsville.
Many of the Wildcats had a hand in the victory, but Miller's two main contributions came when Williamsport needed them most.
"It definitely helps when some one steps up like that," Williamsport coach Kristi Gee said. "It was especially needed when we were playing in a court like this with the different ceiling and floor. (Miller) came through with both her serving and her kills."
The odd surroundings made both teams tentative coming out in the first game. Essex hosted four matches on Tuesday - Class 1A and 4A semifinals - and had two courts playing simultaneously. The gym's roof was high and had a dome feel to it while the floor was tartan, instead of wood, and had numerous lines on it to set up the boundaries to be used for various sports.
Perryville took an early 3-1 lead in the opening game before Williamsport knotted the game at 3-3 on a pair of service points by Lindsey Plotner.
Miller stepped to the service after four consecutive sideouts and drew all three aces she had in the match, first with a blast that tied up the Panthers' Joelle Borber, who had the serve come at her body in the middle of the back line.
Miller followed with a pair of drop serves that Perryville failed to dig out, starting an eight-point serving run that separated the Wildcats and vaulted them to a win in the first game.
In the second game, Perryville again jumped to a 3-1 lead. Miller moved into the front line and cashed in on six kills, four for points and two for sideouts, to move Williamsport to a 5-3 lead. Plotner added two kills and Denise Sullivan scored two aces as Williamsport scored 14 straight points to get the upper hand in second game.
"The seniors have stepped up all season," said Miller, who finished 12 kills and 13 digs. "Passing is the key for us and as long as we pass, we get the hits. But today, in this gym, it was tough. We needed someone to step up and say 'No matter where the pass is, it's OK, we'll hit it.'"
Williamsport ran off to a 12-1 lead in the third game, led by six serving points by Plotner. The Wildcats hit the pause button on their progress, allowing Perryville to run off a 8-1 run to get within 13-8 before getting the last two points on serves by Jamie Pritchett and Sullivan to close out the match.
"We were on 12 points way too long," Gee said, with a nervous smile.
Plotner finished with eight kills and Pritchett had 12 digs for Williamsport while Sullivan added 17 assists and Staci Grabill passed out 14 more to help the Wildcats' attack.