San Marcos suffered its first Channel League loss of the season on Tuesday night in a 25-15, 25-17, 25-12 sweep at Ventura.
The result leaves the Royals and Cougars tied for first place with 4-1 records.
Ventura, which was swept in the league opener at San Marcos, held Chloe Allen to just eight kills. Kamille Williams added six kills.
Ventura was led by outside hitter Sammy Slater with 16 kills and middle Aubrey Knight with 14 kills and three blocks.
Royals head coach Erica Downing said the team didn’t play well “at all” and will have to rebound on Thursday in a match against Buena. San Marcos is 19-4 overall.