He received a first-round bye before falling, 6-0, 6-0, to Maximilian Hawkins of Chadwick in a second-round match.
"It's a good experience for this being my first time," Simonyan said. "There are a lot of top players in this tournament and they are very strong.
"My goal is to practice hard and come back here next year."
In doubles competition, Flintridge Prep's duo of Kent Byun and Eric Kazangian fell in their first-round match, 6-3, 6-7 (5-7), 10-8, to Benson Lu and Alvin Huang of San Gabriel.
The participants entered Friday's action learning their draws about 30 minutes beforehand.
Simonyan, who finished his season 39-15 and helped the Tornadoes advance to the playoffs for the first time since 2003, drew a bye, giving him more time to prepare.
"He played a very good opponent and it's a great experience to get here as a sophomore," Hoover Coach Julie Hoppe said. "As good as his opponent was, Oleg didn't play his best tennis for whatever reason.
"He wants to come back here next year. You see great players throughout this tournament. Now, he sees how much work he needs to get back and go deeper."
Byun and Kazangian, who helped Flintridge Prep finish second in the Prep league and qualify for the playoffs, finished 35-6.
After falling in their first set, the duo bounced back with an exhausting tiebreaker victory.
Flintridge Prep Coach Ron Catano said Byun and Kazangian were laboring entering the super-tiebreaker.
"Their players gave Kent and Eric every chance to win, but they just couldn't grab it," Catano said. "They just couldn't finish off the points.
"Kent and Eric played well in the super-tiebreaker, but they just got a few unlucky bounces. They had the pressure of playing behind virtually their whole match."