Burroughs (3-6) mustered only one assist in the opening half, where it committed nine of its 14 turnovers as it trailed at the break, 26-19. The Indians fell behind by double-digits early in the second quarter and trailed by 20 late in the third.
"Offensively, we looked confused. We don't know what we're trying to accomplish," Burroughs Coach Vicky Oganyan said.
"A lot of young players and a couple people coming off injuries. I'm not using that as an excuse. We've had four months of practice. But we looked like we had no clue."
West Ranch (5-4) opened the third by scoring eight straight points. After a timeout and ensuing Burroughs bucket, the Wildcats went on a 10-4 run and closed out the quarter with a 44-27 lead.
"Me just coming back, everything's been changing," said Shellmire, who helped lead the Indians last season to their first league championship in 32 years. "We haven't been able to run our offense together as a team and we're just trying to jell right now."
Sidney Ortega scored 11 of her game-high 14 points in the fourth quarter to narrow Burroughs' deficit to 50-40 with 1:34 to play.
The sophomore guard scored 11 of the Indians' 13 points in the final quarter.
Shellmire, who commanded a double-team almost every time she touched the ball, scored only three points in the second half — all in the third quarter.
"Second game back — we still don't know how to play with her or look for her," Oganyan said. "They don't know how to accomplish stuff with her in the game because they haven't played much with her.
"We just have to look at it and learn from it. The hard part of the tournament is you can't practice [before] the next game, but it helps us in a way where we try to fix our problems before league [play] begins."
Burroughs, which beat Sylmar, 65-16, in the tournament's opening game, plays in the winner's consolation game today at 9 a.m. against Harvard-Westlake.
Whitney Branham and Michele Arima scored 12 points apiece to lead West Ranch.