The two began to competitively clash during the 1979 season as the Expos managed two consecutive series sweeps of the Phillies, taking control of the division headed into June.

The Phillies slowly fell out of contention for the division lead as the sweep by the Expos culminated in a six-game losing streak for Philadelphia, ultimately placing them third in the NL East by the end of the month.

Things continued to spiral out of control for the Phillies as they lost five critical series matchups against the Dodgers, Cardinals, and Cubs, bringing them down to fourth in the division.

Montreal struggled through much of May, including two four-game sweeps at the hands of the San Francisco Giants and St Louis Cardinals.

The two teams met for their final matchup of the season with the Phillies leading by six games after the Expos endured a two-game series loss to the Houston Astros.

During the first game in Montreal, Expos hearing-disabled rookie Curtis Pride doubled home two runners and scored on the following play during his first major league at-bat.

After the game, Pride claimed he couldn't hear the ovation but he felt the vibration of the 45,757 Expos fans in attendance at Olympic Stadium.

2002 and 2003 saw both teams struggle to appear in the postseason despite both managing several winning seasons but usually falling short as the Atlanta Braves often controlled much of the NL East.

Budgetary issues heavily affected any free agency or postseason aspirations for the Expos after former owner Claude Brochu sold the team to American Businessman Jeffrey Loria in December 1999.

Prior to the start of the 2012 campaign, the Nationals had endured several incidents of Philadelphia fans overtaking their home games during the series.

[32][33][34] The campaign proved successful as Nationals' home attendance grew substantially as the team qualified for the postseason, clinching the division title after back-to-back defeats of the Phillies in their final series of the season.

Longtime pitcher (and 2019 World Series MVP) Stephen Strasburg opted out of the remaining four years left on his contract, becoming a free agent.