Which team was the first NHL champion (1918)?

The Toronto Arenas were the first NHL champion in 1918. They won the inaugural NHL season's championship series and then defeated the Vancouver Millionaires of the Pacific Coast Hockey Association to capture the Stanley Cup.

The NHL had been formed in November 1917 after the National Hockey Association suspended operations. Toronto won the second half of the split NHL regular season, then beat the Montreal Canadiens in a two-game, total-goals playoff to become the league champion.

The team-name history creates a common source of confusion. The club played in 1917–18 without an official nickname and was often called Toronto or the Torontos. Because the team was operated by the owners of Arena Gardens, historians commonly refer to it retroactively as the Toronto Arenas; that name became official after the season.

Toronto defeated Vancouver three games to two in the 1918 Stanley Cup Final. The franchise later became the Toronto St. Patricks and, in 1927, the Toronto Maple Leafs.