Natalie Lathrop banked in a right-wing 3-pointer at the final buzzer to give fifth-seeded Marshwood a 46-43 win over fourth-seeded Greely in a Class B South girls basketball quarterfinal Friday at the Portland Expo.

Lathrop, who led all scorers with 17 points, had to hurry her shot after receiving a knee-high pass from Maddison Poitras, who gathered a loose ball with time running out.

Marshwood (14-5), which played exclusively Class A schools during the regular season, advances to a semifinal at 6:45 p.m. Wednesday at the Expo against No. 1 Gray-New Gloucester or No. 8 Freeport.

Marshwood trailed 9-2 after one quarter but used a 20-7 second-quarter advantage to take a 22-16 halftime lead.

Greely (13-6) had the edge in the third quarter behind the shooting of Hannah Hussey and Avery Bush, who combined for 14 of the Rangers’ 19 points, and tied the game at 35-35.

Marshwood forged ahead again in the fourth on 3-pointers by Jolie Folger (eight points) and Isabelle Tice (14 points) before Greely tied it on a 3-pointer from Bush.

Bush and Hussey each finished with 11 points.