With baseball season under way, Drew Barrymore and Jimmy Fallon are hoping to hit one out of the park with their new romantic comedy, "Fever Pitch." (search)

Directors Peter and Bobby Farrelly, better known as "the Farrelly brothers," (search) bought the rights to British author Nick Hornby's novel of the same name, but replaced the book's soccer team with the Boston Red Sox (search) to better suit American audiences.

Blind luck landed the Farrellys at Fenway Park (search) as Boston actually started winning and the Red Sox finally ending the curse of the Bambino (search) to win their first World Series since 1918.

"It was a total whirlwind — it was so much fun. It was a pleasure to incorporate these changes because we didn't just abandon the film we were making. It was like it was just enhancing it," Barrymore told FOX News.

The filmmakers scrambled to adapt the story, which originally ended with the Sox losing yet again. The Farrellys even managed to sneak Barrymore and Fallon on the field in St. Louis after Boston won the championship last fall.

"We were flying to St. Louis and we had to film it. I mean you know the guy's like the ultimate Red Sox fan the year that they win. It was the coolest. I couldn't think of a better Hollywood ending," Fallon told FOX.

The surprise real-life victory gave the filmmakers leeway to go sugary sweet with a fairy-tale conclusion that would have been dismissed as Hollywood fluff had it not actually happened, wrote Associated Press movie critic David Germain.

"'Fever Pitch' is stripped of almost all the [Farrelly] brothers' usual crudeness and proves what we've suspected all along: That beneath the gross-out gags and freak-show humor, Peter and Bobby Farrelly are just a couple of lovable romantics," Germain said in his review.

The movie runs a bit dull and choppy early on, Germain said, but the laughs build along with the momentum as the season progresses and Ben's compulsion mounts.

"It all adds up to the most un-Farrelly of Farrelly brothers movies, a straight-on romantic comedy that dispenses with the indelicate humor of such flicks as "There's Something About Mary" and "Shallow Hal," he wrote.

Germain, who gave the movie three stars out of four, also compliments the movie's stars.

"Drew Barrymore (search) is at her most likable as a driven career woman who runs into foul territory when she falls for a man maniacally devoted to the Boston Red Sox. And as the Sox disciple, Jimmy Fallon (search), presents understated charm and cheeriness lacking in last fall's 'Taxi,' his miserable big-screen debut as a lead player."

Fallon plays Ben Wrightman, who caught Red Sox fever when his uncle took him to a game at Fenway Park when Ben was a boy. Ben inherits his uncle's season tickets near the Sox dugout and never misses a game. His apartment is dementedly festooned with memorabilia towels, sheets, a shower curtain, even a replica of the Green Monster, Fenway's outfield wall, in the living room.

A math teacher, Ben meets business consultant Lindsey Meeks (Barrymore) on a field trip with his students. It's not exactly love at first sight, but Ben's gentle humor and gallantry soon win Lindsey over.

Ben confesses his Red Sox fixation early on, but Lindsey does not realize the all-consuming passion of the sports zealot until the height of summer, when she's too far into the relationship to back away without getting hurt.

"It's real stuff and it's real problems and I think that's why women can relate to it, because like how much of yourself do you give up to make a relationship work?" Fallon told FOX.

FOX News' Mike Waco and Lisa Bernhard and the Associated Press contributed to this report.