Then four-time all-NCMC senior guard Brooke Costley took over, scoring 11 points during an 18-4 third-period spree to give the Lady Bulldogs a 50-33 victory on their home court in the long-delayed first-round of the Class 4, District 8 Tournament.
"That's been our bugaboo all year," admitted Lady Owls head coach Tony Willis. "I told the girls going out there, 'We've got to be ready to go third quarter.'"
Marshall was ready in the opening frame, getting a spark off the bench from sophomore Lauren Hare with a pair of three-pointers for a 10-8 lead.
"Lauren can shoot. That's the thing we want he to do," Willis said. "Lauren's a big part of our future, and showed why she will be."
Junior Karson Heying got loose twice inside to extend the margin to 15-11 early in the second period, but Mexico got a bucket from senior Anne Baker and a Costley bomb to pull ahead.
Hare hit from the elbow and senior Stephanie Markes scored off the offensive glass, but sophomore Alison Mudd snapped a 20-all tie with a buzzer-beating three. Still, the Lady 'Dogs' 12-game winning streak over Marshall, including 21- and 19-point margins of victory earlier this season, appeared to be in jeopardy.
However, the Lady Owls' offense went flat to begin the second half -- without a score until senior Jawshawna Terry's stick-back with 3:30 left in the third stanza to snap Mexico's 10-point run. After missing seven of eight shots from the field during the first half, Costley knocked down an 18-footer and a pair of threes -- then fed junior Kelli Ingrum off a baseline drive -- for a 33-20 lead.
"Every time we stepped out on Costley, she stepped out further," Willis said. "We've concentrated so much on our help defense ... we needed to help less and concentrate on our man."
Mudd made a lay-up, Costley buried her fourth trey and junior Remington Greenwell converted a three-point play to extend the gap to 41-22.
Four of Marshall's first five possessions of the fourth quarter ended with turnovers, which would total 20 for the game. Such was the effect of the absence of two of the Lady Owls' best ballhandlers, sophomore Molly Evans and senior Alex Bledsoe.
"The kids have to step up a little bit," Willis said. "We talked about patience ... but we didn't do that in the second half."
Costley finished with 19 points and four assists and Baker contributed eight points, eight rebounds and five assists for Mexico (15-10) -- which will take on No. 2 seed Helias in today's semifinal round.
Marshall (12-13) got 10 points from Terry and eight boards from sophomore Makala Colbert while closing the season with its eighth straight defeat. The Lady Owls will lose two starters from their six upperclassmen, but is poised to continue the progress which saw them post their highest victory total since 2008.
"The biggest thing I'm going to need from those kids returning is picking up on what those seniors did: tough defense, leadership and chemistry," Willis noted. "You can't replace that on a high school basketball team."