The Thoroughbreds will play Eastside at 4:30 p.m. Saturday at Memorial Stadium in Columbia for the title.
South Aiken extended its shutout streak to six, including all four postseason matches.
The state semifinals game was the third contest between the two schools this season. South Aiken won at Airport, and the Eagles returned the favor in the rematch. But Tuesday's postseason matchup was one sided from the start.
Just over 10 minutes into the game, senior team captain Dan Riley's header, off a Michael Poole throw in, gave South Aiken an early lead. Junior Allen Grier scored on a pass from Van Pelt 10 minutes later, and Van Pelt gave the home team full command with a goal early in the second half.