The trade came to be widely regarded as one of the most one-sided deals in hockey history, as Boston immediately became a powerhouse, moving from a last place team to a perennial power. While Esposito became a preeminent star in Boston and Hodge became a league All-Star, Stanfield centered the team's second line, with wingers John Bucyk and Johnny McKenzie—which some considered the best second line in hockey—as well as playing the right point on the Bruins' feared top power play unit, helping the team to lead the league in power play goals every year between 1969 and 1972. He scored 20 or more goals in every one of the six years he played for Boston, with the Bruins leading the league in goals in each of those seasons. He became noted for a heavy slap shot, making his mark in the first game of the 1970 Stanley Cup Finals against the St. Louis Blues when he fired a shot so hard it split Blues goaltender Jacques Plante's mask in half, giving Plante a concussion which sidelined him for the remainder of the playoffs.