Riverside blanked West Liberty-Salem 12-0 in five innings in the Acme sectional baseball tournament Sunday night at Blue Jacket Park.
Trey Lane fired a three-hitter with five strikeouts.
Lane and Dillon Roof each had three hits.
Landon Kelsey, Trey Long, and Trey Helmlinger each added two hits.
The Pirates (7-2) advance to the winner's bracket semifinal against Bellefontaine Tuesday night at 8:30.
Bellefontaine defeated Triad 7-0 on Saturday.