Kortney Eshelman followed with an ace - one of five in the game - and Sabrina Harbaugh ended the match on a return that the Trojans (2-1) let fall to the middle of the court.
"With a lot of our matches we're sluggish in the first game," Eagler said. "To come out and win like we did was huge because then we're not playing catch up."
Ignited by the first game, Greencastle continued to cover the court with fury in the second game. While returning most of Chambersburg's attacking opportunities, the Blue Devils began to set up their offense more as the match progressed. Sixteen of 25 points in the second game were by six different Blue Devils.
"This is a nice team," Eagler said. "I feel like I can throw anyone in there and we can do well. It's a deep team."
On the other side, personnel issues were troublesome for the Trojans, who were missing two starters - Steph Addleman and Ashlyn Rebok - due to injuries.
"We had to jumble up the lineup and put some people in positions that they weren't comfortable with," said Chambersburg assistant coach Bobby Culler, who filled in for head coach Ty Frelin.
Greencastle completed the sweep by holding off a late charge by Chambersburg in the third game. The Blue Devils scored seven of the first eight points of the game and later led 23-17, but the Trojans scored four straight points to cut the deficit to two, leading Eagler to call a timeout.
"I basically just told them that we came this far and there's no way we can let up," she said.
On the next play, Harbaugh passed to Eshelman, who set Lutz with a kill to give the Blue Devils a 24-21 edge. The game ended on an unforced error by Chambersburg, its 23rd of the game.
"It was a lack of intensity and a lack of desire," Culler said. "(Greencastle) went after it every play. They weren't satisfied with the ball hitting the ground."
Negley finished with nine kills, Julia Stein had seven and Lutz added six for the Blue Devils. Amanda Ritchey had 18 assists and Eshelman added 15.