BOSTON — Interviewing Will Ferrell and Will Arnett at the same time can have its enjoyable challenges. Like getting a straight answer out of either of them. Sometimes, it’s just better to let them talk.

“That’s a really good, fantastic question,” Ferrell replied at one point. “One I was not prepared for. [Expletive].”

Both men were in Boston on February 13 promoting the upcoming New Line comedy Semi-Pro. The film plays on an old concept: a weak sports team finds new reason to succeed and must beat tough odds to reach victory. Movie fans may find the familiar premise lacking freshness. So, too, at first, did the filmmakers.

“Arnett took me aside and said, ‘This is not fresh,’” Ferrell said.

“The first day I walked on the set, it stunk,” joked Arnett, who plays sports commentator Lou Redwood and played Gob on Arrested Development. “It literally was not fresh in the building. I said, ‘It smells like Major League in here. With a dash of Tin Cup.’”

But everyone loves a “come-from-behind story,” Arnett said, and Semi-Pro’s Flint Tropics are even bigger losers than most sports underdogs. The worst team in the ABA, a real-life ’70s basketball league, the Tropics must quit playing or join the NBA by raising their rank.

“It’s not [a competition] to win at all,” said Ferrell, who stars as Jackie Moon, a one-hit-wonder artist who owns, coaches, and plays power forward for the Tropics. “It’s literally for fourth place. So, there’s a little bit of a twist there.”

Another twist comes from the film’s setting — in the 1970s. Ferrell last visited the decade with Anchorman, and though his new film only needed the era for the ABA hook, the “intrinsically funny” decade throws Semi-Pro some easy laughs.