The 1918 Stanley Cup Final was contested by the National Hockey League (NHL) champion Toronto and the Pacific Coast Hockey Association (PCHA) champion Vancouver Millionaires. In a series held entirely in Toronto, the Toronto team won the series by three games to two in the best-of-five game series to win the Stanley Cup. It was the first series contested by the new NHL and subsequently the first Stanley Cup win by the Toronto NHL franchise team.
Prior to the 1917–18 season, the National Hockey Association (NHA) had suspended operations as the result of a power play to oust Toronto Blueshirts owner Eddie Livingstone. The remaining clubs then met in November 1918 to form the NHL, using the exact constitution and playing rules of the NHA. The NHL took the NHA's place in competing for the Cup in a playoff with the PCHA.
The Toronto NHL players were assigned from the Toronto NHA franchise, and played for a 'temporary' Toronto NHL franchise, operated by the Toronto Arena owners. This is why it is often called the 'Arenas' although no Arena hockey club existed until after the 1917–18 season. The team at the time used no nickname; and it was often referred to at the time as the "Blueshirts', the nickname of the NHA franchise, as it was announced by the NHA that the franchise had been sold, although this had not been agreed to by Eddie Livingstone, who wanted to resume his franchise, or be compensated under his terms.
Despite this black cloud over it, Toronto won the second half of the split regular season while the Montreal Canadiens won the first half. Toronto then won the NHL title by defeating the Canadiens in a two-game total-goals series, 10–7.
Meanwhile, Vancouver finished the 1917–18 PCHA regular season in second place with a 9–9 record behind the 11–7 Seattle Metropolitans. However, Vancouver beat Seattle in that league's two-game total-goals finals, 3–1, with a 1–0 game two victory.
As with the three previous NHA-PCHA Cup Final series, the series alternated between the NHL champion and the PCHA champion each year, while the differing rules for the leagues alternated each game. This meant that all of the games for the 1918 championship series were played at Toronto's Arena Gardens.
Two of the major differences between the two leagues' rules proved to be a major factor in the series. The PCHA allowed forward passing (adopted in the 1913–14 season) and played with seven players per side; the NHL did not adopt forward passing until the following season, and only played with six players. In every game, the winner was the one playing under its league's rules. The Torontos won Games 1 and 3 with victories of 5–3 and 6–3, and the Millionaires recorded 6–4 and 8–1 wins in Games 2 and 4. Because game five was played under NHL rules, it helped Toronto's Corbett Denneny to score the series winning goal in a 2–1 victory. The Torontos outscored the Millionaires by a combined total of 13–7 in the three games played under NHL rules. Conversely, Vancouver recorded a 14–5 margin in the games under PCHA rules.
Toronto goaltender Hap Holmes recorded a 4.20 goals-against average during the series, while Alf Skinner led Toronto with eight goals. Cyclone Taylor scored nine goals for Vancouver.
Although the Vancouver team was not the winner of the series, the Vancouver club had the words "Vancouver/Defeated Seattle/1917–18/Score 1–0" engraved on the Cup after winning the PCHA championship over the Metropolitans, who won the previous year's Cup finals. This was consistent with the practice at that time of the trophy being officially passed on to the winner of the league championship of the previous Cup champion's league.
The Toronto club never did engrave their name on the Cup to memorialize their series victory over Vancouver. At the time, the NHL club was in a dispute with the owner of the NHA Toronto franchise holder over the Stanley Cup revenues. In 1948, the NHL engraved "1918 Toronto Arenas" on the Cup.
Dick Carroll was not only the first NHL coach to win the Stanley Cup in his first NHL season, Carroll was also a rookie coach.