They say the smaller the ball, the better the sports movie. If that's the case, why hasn't Hollywood made more movies about tennis, which uses a very small ball indeed?

The answer, I suspect, lies in the fact that most Americans regard the sport as only slightly more interesting than an all-day tax seminar.

Nonetheless, “Wimbledon” — starring Paul Bettany and Kirsten Dunst as tour hopefuls who conduct a romantic serve-and-volley at pro tennis’ premier event — lends a certain credence to the small-ball theory. It's a keenly scripted, disarmingly funny sports romp with glamour, suspense and a refreshing spritz of dry British wit. Directed by Richard Loncraine (“Richard III”), “Wimbledon” plays out like Britain's answer to “Bull Durham.” Bettany (“A Beautiful Mind”) is brooding and affable as Peter Colt, an aging would-be tennis star who once peaked at No. 11 in the world but never realized his ultimate dream: winning a Grand Slam tournament.

Now mired in permanent obscurity, Peter receives an at-large invite to Wimbledon, where he plans to retire after what will surely be a quick exit. Strangely, it doesn't happen that way. After a chance encounter with rising American star Lizzie Bradbury (Dunst) — which quickly leads to comfortable banter and hotel room sex — Peter's game takes on new life. To his utter shock, he finds himself in the second round, then the third round, then the semi-finals.

At the same time, Peter and Lizzie embark on a torrid romance, evading her controlling Svengali/father (Sam Neill) and ducking the paparazzi, who all want a piece of tennis’ new fun couple. Peter's apparent astonishment at his windfall is one of the enduring pleasures of “Wimbledon,” and director Loncraine — with help from scripters Adam Brooks (“French Kiss”), Jennifer Flockett and Mark Levin (“Madeline”) — deftly places us inside of the character's head, where we witness the mad rush of anxieties and random thoughts that accompany every break point. The role is a great fit for Bettany, who serves notice that he can play a leading man with the best of them.

Which brings up a certain romantic imbalance in “Wimbledon.” We can see why Lizzie responds to Peter, who peppers his speech with sparkling British witticisms such as "Shut up, you silly ponce!" and "Love isn't just blind — it's bloody stupid!" Peter's attraction to Lizzie is a bit less credible. The screenwriters present her as something of a skanky hothead, making her moments of sweetness and light seem strangely discordant. Nor do we care much when her affair with Peter has a corrosive effect on her game.

And that serve! To even the untrained tennis eye, it will be painfully obvious that Dunst would be lucky to win a match at a high school tournament, let alone Wimbledon.