Toronto Blue Jays
Montreal Expos
### Montreal Expos

The [Montreal Expos](/wiki/Montreal_Expos "Montreal Expos") were the Blue Jays' geographic [National League](/wiki/National_League_%28baseball%29 "National League (baseball)") rival, being the other Canadian MLB team before it was relocated. From 1978 to 1986, the teams played an annual mid\-season exhibition game known as the [Pearson Cup](/wiki/Pearson_Cup "Pearson Cup"), named after former [Prime Minister](/wiki/Prime_Minister_of_Canada "Prime Minister of Canada") [Lester B. Pearson](/wiki/Lester_B._Pearson "Lester B. Pearson"). The teams began facing each other in the regular season in 1997 with the advent of [interleague play](/wiki/Interleague_play "Interleague play"). During the 2003 and 2004 seasons, the Expos' last two seasons before relocating to Washington, D.C., as the [Nationals](/wiki/Washington_Nationals "Washington Nationals"), the Pearson Cup was awarded after a pair of three\-game sets.


Why was the Pearson Cup exhibition game significant to the teams' rivalry?