Drew Barrymore shoots for the film Fever Pitch in Boston?s Fenway Park. (AP)

Los Angeles, Nov. 1 (Reuters): The Boston Red Sox?s historic World Series baseball win on Wednesday has forced a rewrite of a sports-based romantic comedy starring Drew Barrymore and Jimmy Fallon.

Fox?s Fever Pitch, which is set during the 2004 Red Sox season, stars Barrymore as a woman who falls for Fallon?s Red Sox-obsessed sports addict. It is in production in Toronto and depicts the Red Sox losing just as the baseball team has for the past 85 years.

?We had gone into the movie anticipating that the Red Sox would not win the World Championship, and it would be another dismal ending for them, but love would conquer all,? said Peter Farrelly, who is directing with brother Bobby. ?But what happened because of this turn of events, we now have the double whammy of a happy love story and a championship team at the same time.?

Because of the reversal of fortune, screenwriters Lowell Ganz and Babaloo Mandel, who Americanised English author Nick Hornby?s football novel, have been in rewrite mode to incorporate the championship run.

The film was shot in Boston?s Fenway Park last month, incorporating actual games into the movie.

?Had we made this ending up, it would have been considered too trite,? said Nancy Juvonen, a producer on the film. ?Now the happy ending isn?t just for our couple, it?s a happy ending for the team and all underdogs.?