Jake Scott scored four goals and Steve Hildebrand had two. Brandon Bassett scored a goal and assisted on two others.
Conestoga, which nipped Strath Haven, 11-9, earlier in the season, led, 5-4, before its end-of-half spurt.
Jack Borbee and Tucker Carney each scored three times for Strath Haven, the 22d seed.
Also in the District 1 playoffs:
Central Bucks East 12, Council Rock North 2. The host, No. 4 seed didn't allow a goal at even strength in a victory over No. 29 Council Rock North. Matt Schmidt scored four goals and Owen Griffin, Ryan Brown, and Matt Heim had two apiece. Dustin Buchanon caused seven turnovers.
Ridley 15, Upper Moreland 4. Brock Anderson scored three second-half goals, and the seventh-seeded Green Raiders pulled away from the No. 26 seed. Nick Fox, Lou Harrison, Bill Rouse, and Cade Stratton tallied two goals each for the hosts.
Holy Ghost Prep 12, W.C. Henderson 6. Andrew Rose went 12 for 18 on faceoffs, and the 13th-seeded Firebirds held off the visiting No. 20 seed. Alex Yabe scored twice and had four assists. Bennett Zaba had three goals and two assists. Greg Price made 14 saves.
Owen J. Roberts 13, Perkiomen Valley 7. Christian Wood made 14 saves, and Chris Antich and Austin Delgatto scored four goals each to power the No. 14 seed at home. Matt Baker scored twice for No. 19 Perkiomen Valley.
Avon Grove 14, Plymouth Whitemarsh 0. Will Schreiner scored a first-half goal and made five saves in net as the fifth-seeded Red Devils cruised past visiting, No. 28 Plymouth Whitemarsh. Tanner Peck added four goals, and Stephen Cryon had three.
Nolan Cummings belted a grand slam in the fifth inning, and Cardinal O'Hara advanced to the Catholic League semifinals for the first time since 2007 by winning at Neumann-Goretti, 5-2. Matt McGraw made an over-the-shoulder catch in left-center with two men on and two outs in the fourth inning to preserve the lead. Chris Fusaro shut the door with three innings of scoreless relief.
Conor Smith went 2 for 4 and drove in three runs, and Roman Catholic beat host La Salle, 8-4, in another quarterfinal game. Mike Opeila had two hits and two RBIs.
Inter-Ac. Zach Weilgus struck out seven in six innings, and Penn Charter clinched a share of the league title by winning at Episcopal Academy, 2-1.
Frank Cresta hit a homer to give Haverford School a 3-2 victory over Malvern Prep. Ben Tracy threw a five-hitter. With the loss, Malvern Prep had to share the league crown with Penn Charter.