"You could tell she was less experienced and didn't keep composure, maybe," Petrini said. "That's a big part of it, the mental game. I have [experienced that]."
On the other side of the No. 1 bracket, Morgantown veteran Stephanie Arnold takes on Parkersburg's Sloane Prince. At No. 2, the Big Reds' Cassandra Powell will play University's Meghan Zerkel, while Huntington's Kate Huck faces Hurricane freshman Kayla McKnight.
McKnight survived one of Thursday's best matches, rallying from a 7-6 deficit to win 9-7 over Morgantown's Abby Rosiello. She came back from 15-40 to hold serve at 8-7, then broke to win the match.
In boys AAA, GW's Zack Koenig will battle Huntington freshman phenom Hunter Tubert, while Ryan Massinople battles former No. 1 champ Robert Skolik at No. 2. The Patriots also face the Highlanders in No. 4 singles and No. 3 doubles.
"I play with him four nights a week, so I really know him well," Massinople said of Skolik. "I think I've got a shot at it. If I play my game, it should be a fun match."
Opposite Koenig and Tubert in the No. 1 bracket is a serious contender in German exchange student Max Schulz Mullensiefen, playing for Morgantown. He plays Grant Davis of Martinsburg in the first semifinal.
Mullensiefen made quick work of Capital's Joe Michael, who was coming off his 8-3 revenge win over Hurricane's Reid Bailey in the first round. Like Tubert, Mullensiefen did not lose a game Thursday.
"The kid's a monster," Michael said. "I was expecting it, though. There's nothing I can really say. He's got a monster serve, and that helps his game a ton."
In the boys top AA-A singles, Catholic's Mark Cassis plays Oak Hill's Matt Holliday, with Max Meade of St. Joseph and Nick Conforti of Madonna in the other semi. Irish players won their four matches by a combined 32-4.
Defending girls No. 1 champion Mary Emma Maddox of Catholic takes on sophomore Carly Killmer of Shady Spring, who ousted Natalie Capito of Wheeling Central in a 7-4 tiebreaker.
The remaining quarterfinals are pro-set matches, with semifinals expanded to best-of-three sets.
Reach Doug Smock at 304-348-5130 or dougsm...@wvgazette.com, or follow him at twitter.com/dougsmock.