Former Major League Baseball rivalry between the teams in Canada
Locations of the Toronto Blue Jays and Montreal Expos in 2004
The Pearson Cup () was an annual midseason Major League Baseball rivalry between former Canadian rivals, the Toronto Blue Jays and Montreal Expos. Named after former Prime Minister Lester B. Pearson, it was originally created to raise money for minor league baseball in Canada. In later years, it was incorporated into the interleague baseball schedule.
The series began in 1978, and ran until 1986. Due to a strike, no game was played in 1981. In 2003, the series was revived as part of the Blue Jays–Expos interleague rivalry. It continued on into the 2004 season, after which the Expos moved to Washington, D.C., and became the Washington Nationals. The cup is now on display in the Canadian Baseball Hall of Fame in St. Marys, Ontario.
Results.
From 1978 to 1986, the Cup was awarded after a one-game exhibition, that had no effect on the major league standings. The 1979 and 1985 games were abandoned as ties due to time constraints; in 1979 the Expos had to catch an airplane flight, while in 1985 the Jays had to catch a flight.
The game was suspended in 1987 as the two teams could not find a mutually agreeable date to play the game. There was discussion about reviving the game in the preseason, or playing it in another Canadian city such as Vancouver, but this never took place.
During the 2003 and 2004 series, the Cup was awarded after a six-game set, three in Toronto and three in Montreal. These games counted in major-league standings and were played during the regular season.
The All-Canadian Series.
The Blue Jays and Expos first played meaningful baseball in the season with the introduction of interleague play, with the teams being designated natural rivals. In 1997, the teams played three games at Toronto; the two teams played home and home series for the first time in 1998. The series was a decided boost to the paltry attendance numbers at Olympic Stadium in Montreal, and gave a modest increase in attendance at SkyDome in Toronto; it failed, however, to become a serious rivalry amongst the players or the fans. Some people attribute this to a lack of Canadian players on both teams, while others point to the general discontent of Canadians with Major League Baseball during the late 1990s and early 2000s.
Major League Baseball put the final nail in the Series' coffin by playing the final set between the Jays and Expos in San Juan, Puerto Rico instead of Montreal. Major League Baseball's intention to boost attendance by playing in San Juan ended up resulting in lower attendance than the series had attracted in Montreal a year earlier.
The All-Canadian Series ended after when the Expos were relocated and became known as the Washington Nationals. The Blue Jays won the series 24 games to 19 games, and Toronto also won the most season series (3–2–2).
Season-by-season results.
The two teams met annually from 1997 to 2004 as part of the All-Canadian Series, then met annually again starting in 2023 as a result of the scheduling formula change, meeting intermittently from 2005 to 2022. 
References.
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