In six innings, the 6-foot, 190-pound senior lefthander (2-0) yielded four hits and struck out 10, mostly mixing a fastball and curveball. He threw 108 pitches.
Against 17 of 31 batters, Mayberry gained a 1-2 count.
"When you get ahead like that, you don't have to throw fastballs where they like them," he said.
Mayberry held the Lions to two hits in the first five innings. A hit batsman and a double to right-center field opened the door for two sixth-inning runs and Andrew Bechtold's seventh-inning appearance.
"We had some success against [Mayberry] the last two years," Penncrest coach Steve Silva said. "Today, he hit his spots, was very consistent in finding the strike zone, and kept our hitters off balance."
Mayberry, who opened the season with a six-inning win over Haverford High, doubles as a centerfielder for Garnet Valley (4-1 overall, 3-0 Central). He is ticketed for Marist.
Last summer, the Chadds Ford resident played in showcase events with the All-Star Baseball Academy. His teammates included Penncrest righthander John Geffre and Malvern Prep shortstop Joe Poduslenko,
Mayberry, who struck out all nine of the batters in Penncrest's starting lineup, and Poduslenko are fishing buddies.
"We get pretty competitive," Mayberry said. "We've mostly been going for bass. I think we're going to go for catfish next."
Against the Lions, rightfielder Sean Sarbaugh accounted for half of his team's six hits. The No. 5 batter went 3 for 4 (two doubles) with three runs and two RBIs.
In a three-run fifth, after walks to Mayberry and Jeff Shanfeldt, Sarbaugh (single past third base), Brad Gifford (single to shallow left), and Nick Bulisky (fielder's choice grounder) posted RBIs in making it 6-0.
Penncrest slipped to 2-2 and 1-2.
"We've been inconsistent on offense, scoring a lot of runs in one game and then just a few in the next," Silva said.
Garnet Valley 0102301 - 761
Penncrest 0000020 - 252
WP: Dalton Mayberry. LP: Nick Boleto. 2B: GV-Sean Sarbaugh 2; P-Shane Donnelly. 3B: P-Ronnie DiMatteo.
Contact Rick O'Brien at firstname.lastname@example.org. Follow @ozoneinq on Twitter. Read his blog, "The O'Zone," at www.philly.com/ozone