Goals by Captain Will Klingner and Ben Wurst provided a narrow 2-1 first period lead before the Cardinals began to pull away from the Eagles, outscoring them 4-1 in the second quarter for a 6-2 halftime lead.
A pair of goals by Tyler Triscari, a man-up score by Klingner and a Julian Fraser goal from the two-meter position gave Greenwich control of the game.
Goalie Steven Michaud came up with seven saves in the game.
Following the title game, the GHS boys played three non-tournament games.
In the first, they fell to the Pittsburgh Water Polo Club, 14-9.
Playing what Coach Terry Lowe called "listless and some of its worst polo of the year," the team quickly fell behind 5-0 in the first quarter and, after so many comeback wins this fall, the Big Red finally found itself in too deep of a whole to dig out of against a quality opponent.
Fraser did manage a hat trick, Robinson a pair of goals, with singles from Fraser, Neary, Moss and Peterson.
Playing with more intensity, the Big Red rolled over two teams from Texas in its final day of play.
First, they beat the Thunder WPC from Dallas 25-5.
With ten players in the scoring column, Klingner and Triscari led the way with five goals apiece.
The Cardinals followed with a 20-6 win over the Viper WPC from Houston.
Triscari was again the leading scorer with six goals, followed by hat tricks from Matthew and Julian Fraser and Tim Hardman, whose third goal of the game was the Big Red's final score of the year.
The Cardinals ended the season with a record of 27-2-1, claiming championships in Pennsylvania's Beast of the East Tournament, their own Cardinal Tournament, the Montreal Invitational and the Mid-Atlantic league.