Vermont second baseman Marty Bechina crushed a two-run homer in the fourth to propel the Monsters to victory at Centennial Field on Sunday.
The Lake Monsters went into the inning trailing the Valleycats, but designated hitter Jose Rivas notched an RBI before Bechina put his team ahead.
The home team tacked on a couple more runs in the eighth and took the 6-3 win against the Stedler Division rival Tri-City.
Vermont pitcher Colin Peluse struck out five and allowed one run over three innings for his first professional win.
The Lake Monsters improved to 15-21 this season, while Tri-City fell to 13-21. The squads wrap up this series on Monday, July 22 at 7:05 p.m.