The 1980 Stanley Cup playoffs, the playoff tournament of the National Hockey League (NHL) began on April 8, after the conclusion of the 1979–80 NHL season. This season saw the addition of four teams from the disbanded World Hockey Association (WHA) as expansion franchises, and thus the playoffs were also expanded from 12 to 16 teams. The expanded playoff format allowed two of those former WHA clubs, the Edmonton Oilers and the Hartford Whalers, to make the playoffs in their first season in the NHL. The playoffs concluded on May 24 when the New York Islanders defeated the Philadelphia Flyers 5–4 to win the final series four games to two and win the Stanley Cup. It was the Islanders' first Stanley Cup win and was the first of four consecutive Stanley Cup wins. With the league expansion from 17 to 21 teams, the playoffs were also expanded, from a 12-team tournament to a 16-team tournament. The sixteen teams were composed of the four divisional champions plus the top 12 finishers of the remaining 17 teams. The 16 qualifying teams were then seeded based on regular season points, with divisional rankings ignored. Division leaders no longer received first round byes. The teams were seeded 1 through 16, with the top team playing the 16th team in the first round, and so on. In subsequent rounds, matchups were similarly arranged, with the top remaining seed against the lowest remaining seed, and so on. The Preliminary Round was expanded to be a best-of-five set, up from a best-of-three. The Atlanta Flames played their final playoff games in this postseason, and moved to Calgary soon after; the playoffs returned to Atlanta in 2007. (2) Buffalo Sabres vs. (3) New York Islanders This was the third playoff series meeting between these two teams. New York won both previous meetings in consecutive years, the latter of which was a four-game sweep in the 1977 Stanley Cup Quarterfinals. Playoff seeds The sixteen teams that qualified for the playoffs are ranked 1–16 based on regular season points. Philadelphia Flyers, Patrick Division champions, Clarence Campbell Conference regular season champions, NHL regular season champions – 116 points Buffalo Sabres, Adams Division champions, Prince of Wales Conference regular season champions – 110 points Montreal Canadiens, Norris Division champions – 107 points Boston Bruins – 105 points New York Islanders – 91 points Minnesota North Stars – 88 points Chicago Black Hawks, Smythe Division champions – 87 points New York Rangers – 86 points Atlanta Flames – 83 points St. Louis Blues – 80 points Toronto Maple Leafs – 75 points Los Angeles Kings – 74 points Pittsburgh Penguins – 73 points (30 wins) Hartford Whalers – 73 points (27 wins) Vancouver Canucks – 70 points Edmonton Oilers – 69 points April 29 New York Islanders 4–1 Buffalo Sabres Buffalo Memorial Auditorium Recap May 1 New York Islanders 2–1 2OT Buffalo Sabres Buffalo Memorial Auditorium Recap May 3 Buffalo Sabres 4–7 New York Islanders Nassau Coliseum Recap May 6 Buffalo Sabres 7–4 New York Islanders Nassau Coliseum Recap May 8 New York Islanders 0–2 Buffalo Sabres Buffalo Memorial Auditorium Recap May 10 Buffalo Sabres 2–5 New York Islanders Nassau Coliseum Recap New York won series 4–2