Christian Riley scored 20 minutes into the game, and Michael Guerrero added the eventual game-winner 13 minutes into the second half as Bethel Park scored a 2-1 win over Canon-McMillan (8-6-5) in the first round of the Class AAA playoffs. The Big Macs' Chris Lewis-Kwiatakowski scored with 2 1/2 minutes left in the game. The Black Hawks (12-5-2) will play Peters Township/Baldwin in the quarterfinals Thursday at a site and time that has yet to be determined. • Seneca Valley 5, Plum 1 — After a scoreless first half, Seneca Valley raced past Plum in an opening-round game. Third-seeded Seneca Valley (13-6-0) got two goals from midfielder Josh Allman, as well as tallies from Andreas Fatschel, Rob Wright and Joey Gualtieri. Shane Rings scored the only goal for Plum (7-7-4). The Raiders will face Kiski Area (12-2-2), a 2-1 winner over North Allegheny (10-7-0), in the quarterfinals. Class AA • Mars 1, Burrell 0 — Mars forward Ryan Gralish scored a header off a corner kick with five minutes remaining in the first half for the only goal of the game as 10th-seeded Mars, which has played in the last three WPIAL Class AA finals, began its quest for a fourth consecutive championship game appearance. Mars (14-3-2) dominated territorial play from start to finish but was unable to pad the goal advantage as the Burrell (12-3-2) defense, led by goalkeeper Alex White, frustrated the Planets' snipers. The Planets (14-3-2) will play No. 2 seed South Park (17-1-1), a 7-0 winner over Elizabeth Forward (10-8-1), in the quarterfinals Thursday at a site and time that has yet to be determined. • West Allegheny 1, Steel Valley 0 — Xavier recruit Tyler Graziani scored with 9:01 left in the game to lift West Allegheny past Steel Valley (11-6-1) in a first-round game. The Indians (15-3-1) will play Ringgold (16-0-1), a 5-0 winner over Southmoreland (13-4-2), on Thursday in the quarterfinals. • Belle Vernon 1, Blackhawk 0 — David Wurmlinger scored the lone goal of the game with 20 minutes left in regulation to left Belle Vernon past Blackhawk (16-2-1) in the first round at West Allegheny. The Leopards (17-2-0) will play Quaker Valley/Shady Side Academy in the quarterfinals Thursday. • Hampton 5, Indiana 0 — Hampton recorded its second consecutive shutout after beating Indiana (13-6-1) in a first-round game. Chris Delpozen, Jonathan Mercier, Justin Carter, Quay Subtka and Brian Margarian all scored for the Talbots. Hampton (18-1-0) will play Montour on Thursday in the quarterfinals. Class A ? OLSH 4, California 2 — Matt Sangermano scored three goals and Guiseppe Michelone added one, as Our Lady of the Sacred Heart topped California (9-6-2) in the first round at Ringgold. OLSH (11-6-0) will play Neshannock (18-0-0), a 4-1 winner over Serra Catholic (8-8-0), in the quarterfinals Thursday. • Sewickley Academy 5, Freedom 1 — Teddy Zierden had a hat trick, and J.P. Boweel and Rob Nogay each had a goal for Sewickley Academy in its win over Freedom (9-5-1) in the first round at Quaker Valley. Sewickley Academy (11-4-2) will play Springdale (12-3-2), a 1-0 winner over Bentworth (10-8-1), in the quarterfinals Thursday. • Greensburg Central Catholic 5, St. Joseph 1 — Junior Justin Nolfi and senior Brad Applebee each scored a pair of goals for the Centurions in their win over St. Joseph (9-9-1) in the first round at Hampton. Tyler Dunton also scored for Greensburg Central Catholic. The Centurions (17-3-0) will play Riverside (13-4-1), a 1-0 winner over Vincentian (11-6-1), in the quarterfinals Thursday.