San Marcos regrouped after a tough first set and gave unbeaten Ventura a battle before falling, 25-12, 25-21, 25-23, in a Channel League match at the Thunderhut on Thursday.
Ventura is 13-0 and 2-0 in league.
USC-bound Sammy Slater led the Cougars with 23 kills, while Aubrey Knight had six blocks.
Jenna MacFarlane recorded a double-double for the Royals with 11 kills and 11 digs.
“We continue to play some great defense,” said coach Tina Brown.
Libero Delaney Werner led the Royals with 12 digs. Addy Colburn and Leila Parker had 5 kills each and Taylor Hantgin handed out 15 assists.
The Royals (0-2 in league), play at the Camarillo Invitational this weekend.
— Noozhawk sports editor Barry Punzal can be reached at bpunzal@noozhawk.com. Follow Noozhawk Sports on Twitter: @NoozhawkSports. Connect with Noozhawk on Facebook.