Ahead 4-0 in the third, Wakamatsu crushed a bases-clearing three-run double off the right field wall to give Lynchburg a 7-0 advantage. The shortstop finished with four RBI on the night.
Lynchburg scored six of their seven runs with two out.
Sam Hentges (Win, 1-0), tied a career-high with six innings pitched. The left-hander allowed five hits, three runs (one earned) and struck out five.
Justin Garcia (Save, 1) made his season debut and hurled three hitless innings out of the bullpen.
The Astros scored all three of their runs in the fourth inning. Abraham Toro-Hernandez and Kristian Trompiz each hit RBI singles, and the third run scored on an error.
Alcala allowed three earned runs on two hits, and walked five in 1.2 innings. Carlos Sierra came on in relief and allowed four earned runs in three innings, walking four.
The Astros issued eight free passes to Lynchburg on Wednesday.
The Hillcats (3-4) wrapped up their season-opening seven-game homestand by avoiding the sweep against the Astros.
On Thursday, Lynchburg embarks on their first road trip of the season as the team will travel to Wilmington for a four-game series against the Blue Rocks.
Right-hander Zach Plesac (0-1, 11.57) will make his second start of the season for the Hillcats, opposite of righty Anthony Bender (1-0, 2.25). First pitch is scheduled for 6:35 p.m. at Frawley Stadium.
Max Gun will be on the air with the pre-game show at 6:25 p.m. on TuneIn Radio and the Radio434 app.
For tickets and more information visit Lynchburg-hillcats.com, call 434-528-1144, or stop by the City Stadium box office.