The St. Mary's High girls basketball team upset Mater Dei-Santa Ana 55-41 on Friday in what Panthers coach Nate Fripp called the biggest win in the history of the program.

Mater Dei (11-1), which is No. 1 in the nation in the MaxPreps.com computer rankings, held a 21-19 lead at halftime. But St. Mary's (7-2) went on a key run in the third quarter and didn't trail after that in a Paul Pierce Classic game at Inglewood High.

The run started when Gabby Green got a steal and converted a layup. Taylor Berry also had a steal, a layup and a 3-pointer in the run.

"We just buckled down defensively. We did a good job trying to limit (Mater Dei star Katie Lou) Samuelson specifically," Fripp said in a phone interview.

Samuelson scored 30 points with seven 3-pointers in Mater Dei's 66-53 victory over St. Mary's at the Nike Tournament of Champions on Dec. 20. On Friday, she had 20 points and one 3-pointer.

"If we kept her under 30, we could win," Fripp said.

Green scored 18 points, and teammates Ma'Ane Mosley and Berry added 13 and 12 points, respectively.