Newly minted celebrity couple Vince Vaughn and Jennifer Aniston don't have many opportunities to demonstrate their romantic chemistry in Peyton Reed's funny, heart-wrenching "The Break-Up," but they still give what may be the best performances of their careers.

Aniston, in much greater need of a commercial boost, has the far more sympathetic role, playing Brooke Meyers, an art gallery rep whose love life goes sour in the most conventional way: She's accused of being a nag by a boyfriend she sees as a self-absorbed slob. Brooke and Vaughn's Gary Grobowski - the fast-talking guide of the tour bus he owns with his two brothers - meet cute at a Cubs baseball game in the precredit openings, have a whirlwind courtship summarized in the opening credits, then fall apart after a dinner party at their co-owned condo. With the scent of "The War of the Roses" hanging over their relationship, they continue to live together - she gets the bedroom, he gets the living room - while drawing friends into their increasingly hostile battles.

Developed from an idea by Vaughn, who shares story and producer credits, "The Break-Up" has a sharp edge and a granite center. The punishment Gary and Brooke heap on each other is often laugh-out-loud funny, but the hurt that comes with it feels very real, and while the film has a satisfying ending, its emotional integrity is unusual in the genre.

Director Reed's last film, "Down With Love," was an affectionate spoof of Rock Hudson/Doris Day movies, and though "The Break-Up's" tone is a 180-degree switch, there is a romantic innocence about it, a belief in the foundation of Gary and Brooke's original attraction.

Their behavior may be appalling at times, but you still root for them to get back together. I'd had a neutral reaction to almost everything Aniston did on screen before, but her performance here is genuine, and the scene revealing the depth of Brooke's pain is a killer. It makes you want to give Vaughn a smack. The film is less successful at showing Gary's delayed revelations about his shortcomings, but his is a good performance, balanced between drama and physical comedy. Not enough can be said for the supporting roles. Jon Favreau is very funny as Gary's best friend, Judy Davis is a riot as Brooke's egocentric gallery boss, and John Michael Higgins nearly steals the show as Brooke's a cappella-singing brother.

Given its subject matter, I don't know if "The Break-Up" qualifies as a date movie. But it will serve as a cautionary tale for couples falling in love.