Banner Years: 1976, triple the tension with Celtics-Suns 3 OTs

John Havlicek (17) taking last-second shot during second overtime vs Phoenix Suns, Game 5, Boston, MA 6/4/1976. With him are assistant coach John Killilea (left) and trainer Frank Challant. (Photo by Dick Raphael/Sports Illustrated via Getty Images) NBA history spans 80 seasons, and as CelticsBlog readers well know, the Boston Celtics have won a league-high 18 championships. This month, we are recapping each of those title years.In 1974, the Boston Celtics won their 12th championship in a tensio