As the season produced a tie for the season championship, the defending champion Ottawas and Wanderers played a two-game playoff, with the winner being awarded the Stanley Cup. The series took place on March 14 in Montreal and March 17 in Ottawa. The Wanderers would win the series 9–1, 3–9 (12–10) in dramatic fashion..
Ottawa was installed as 2–1 betting favourites, but the Wanderers upset the bookies. In the first game in Montreal, the Wanderers dominated Ottawa, as Ernie Russell got four goals, Frank Glass got three and Moose Johnson would get two for a 9–1 victory.
After the first game, the Ottawas would replace their goalie Billy Hague with the Smiths Falls goalie Percy LeSueur in to play his first game for the club. Despite being down by eight goals, interest in Ottawa for the return match was high. Rush seats on sale the day of the game produced a throng that caused the ticket seller's glass to break. The venue, Dey's Arena, was modified to hold more spectators, including setting up temporary bleachers, removing the grandstand which had been used as a press box, and the installation of a press box attached to the rafters. Over 5,400 would attend the game and the top $2 tickets were being sold for $10. Betting interest was high, including one $12,000 bet.
After twelve minutes, the first goal was scored by the Wanderers' Moose Johnson to increase the goal lead to nine. Ottawa's Frank McGee, Harry Smith, and McGee again scored before half-time, cutting the deficit to 10–4. Harry Smith would score to open the second half, followed by Rat Westwick. Then Westwick scored again to make it 10-7 before Harry Smith scored three straight goals to make the score 9–1, evening the series with ten minutes to play to tie the series, causing a five-minute standing ovation. With seven minutes to play Smith was sent off for the rest of the game and Lester Patrick would score with ninety seconds to play to put the Wanderers back in the lead. Patrick would ice the game with a goal with a few seconds to play. The Silver Seven reign was over.
The Toronto Globe called it the "greatest game of hockey ever played on Canadian ice, or any other." The Sporting News would later dub it the "Greatest Hockey Game in History." Moose Johnson would end up with the Governor-General's top hat. It had been knocked of the Earl Grey's head, and a fan had snatched it up, giving it to Johnson later in the dressing room.
Because of the need for the play-off, no challenges were made against western teams until the following winter. Ottawa had won Stanley Cup challenges that season, which meant that the 1906 season would have two Stanley Cup holders: Ottawa until March, and Montreal Wanderers for the balance of the year.