The IceCaps fired 48 shots — just short of a team record — at Pirates goalies Peter Mannino and Justin Pogge to open a four-game home stand.
Aaron Gagnon, Zach Redmond, Danny Dries, Will O'Neill and John Albert had the goals for St. John's. For Dries and O'Neill, who scored 15 seconds apart early in the middle period, it was their first pro goals.
Eric O'Dell had three assists for St. John's and was the game's first star.
David Aebischer was solid making 31 saves for the IceCaps.