Audrey Mackie scored 20 points, and top-seeded and undefeated Oceanside survived Yarmouth’s upset bid in the Class B South girls’ basketball quarterfinals, rallying in the second half for a 54-48 victory Saturday at the Portland Expo.

Bailey Breen added 18 points for Oceanside (19-0), which now has a 52-game winning streak. The Mariners trailed for most of the first three quarters and were down by as many as nine points in the third. They went ahead for the first time on an Abby Waterman putback that made it 38-36 with 1:26 left in the third quarter, then took the lead for good on Emily Sykes’s 3-pointer that made it 41-40 with 7:04 remaining.

Neena Panozzo led the eighth-seeded Clippers (8-12) with 14 points, while Maya Hagerty scored 13 and Delia MacDonald added 10.