Host Inglewood never trailed and endured valiant comeback runs by the Indians throughout the game, winning, 74-65.
With the win, the Sentinels snapped Burroughs' 13-game winning streak.
The Pacific-League-champion Indians (25-5) set the school's all-time single-season mark for wins, and Wednesday's quarterfinal appearance marked the deepest playoff run Coach Vicky Oganyan has had in her seven years at Burroughs.
But those accomplishments were overshadowed, at least temporarily, by the loss to Inglewood, which won the Division III-A championship a year ago.
"At the end of the season, you're either going to win a CIF championship or you're going to have a loss," Oganyan said. "For us, the loss hurts, but what we take with us is the journey that we had."
Shortly after the game ended, Burroughs walked back out of the locker room and onto the court where NBA superstar Paul Pierce got his start playing at Inglewood.
Determined, focused and eager expressions prior to the game had transformed into long faces, teary eyes and subtle sniffling.
"We gave it our best," Burroughs senior Lisha Elsenbach said, trying to hold back tears. "It's something you're just never going to forget."
Elsenbach finished with 18 points, five rebounds, four assists, a steal and a block.
Senior guard Chelsea Rhamdeow led the Indians with 22 points, five rebounds and a steal.
"She's become a really good player," Oganyan said of the senior. "Not just this game. Some games in league when Lisha didn't have a great game, she stepped up offensively. The last two playoff games she's been our leader. I can't say enough of how much she's improved."
Inglewood led, 17-11, at the end of the first quarter. It extended the margin to 30-23 by halftime.
The Sentinels (23-7) used full court, man-to-man defensive pressure and mixed in various zone schemes that affected Burroughs on offense. Inglewood had 10 steals in the game, some of which also led to easy baskets the other way.
"That was the key," Oganyan said. "They're very physical."