"We had unforced errors, too many of them," Eggleston said. "You can get away with a few, but if you're giving away two or three points each time, you're getting yourself in a hole. We couldn't get out of our own way."
Buckley's Adiya King also played a pivotal role in Providence's defeat.
King recorded 18 kills, including 13 in the final two games, with a resounding put-away ending the match.
King kept Providence from taking a 2-1 lead in games.
Providence had two game-points in the third game, but a kill from King tied the score at 24. A kill by Providence's Beatrice Yosuico gave the Pioneers a one-point lead and another opportunity to take control of the match. But Buckley responded again, taking advantage of another error and a kill by Marlen Grussi to take the game.
King helped Buckley score six consecutive points in the fourth game to take a 10-4 lead and cruise to the win.
"She has improved since the first meeting," said Eggleston, whose team defeated Buckley in five games on Oct. 5. "They had us scouted really well."
Added Buckley Coach Javy Martinez: "Adiya kept hammering, hammering, hammering and hammering. We stayed aggressive."
Buckley (8-8, 4-3) made adjustments to take advantage of a timid Providence offense.
The Griffins stayed back on defense in the first game, but moved up in the third and fourth games to catch up to Providence's soft hits.
"We compressed our defense," Martinez said. "We needed this."
Even with the loss, Providence should be in position to advance to the playoffs, as the top four teams from the league will earn an automatic posteason berth.
The Pioneers sit in third place, ahead of fourth-place Buckley (4-3) and Glendale Adventist (2-3).