It’s not a great film, but I honestly don’t know how you can make a better movie about tennis than “Borg vs. McEnroe.” 

Here is the solitary combat, the stripped stage where glory or humiliation await, the mental toughness it takes to get up off the mat when the match and the crowd have turned against you. It’s the toughest solo sport out there that doesn’t involve a literal beatdown.

Yes, you could get a grand soap opera out of The Williams Sister Saga,” and who knows? Maybe there’s unspoken tragedy/backstage drama to assorted other great rivalries in the sport, past and present.

But Danish first-time feature director Janus Metz and unheralded screenwriter Ronnie Sandahl have done a fine job of getting into the skulls of two of the sport’s greatest head-cases and a storied rivalry born at Centre Court, Wimbledon.

It was 1980, when the rackets were made of wood and the players made of steel. And none was steelier than the icy blond rock star Bjorn Borg, played here by Sverrir Gudnason. On the court, he was the master baseliner, ripping passing shots by anyone who dared take the net against him, easily outlasting those who thought staying back and waiting for him to make a mistake was a better strategy. 

He was closing in on his fifth consecutive Wimbledon title. And all the brooding, ritualistic 24 year-old Swede could think about was losing. Nobody will remember that he won four in a row, he muses to his coach (Stellan Skarsgard plays Lennart Bergelin), “just that I lost the fifth one.”

John McEnroe (Shia LaBeouf) is the latest upstart to challenge him, a brash and rude American even more brash and rude than the dominant player Borg himself unseated, Jimmy Conners (Tom Datnow, relegated to the background). He’s assaulted a “gentleman’s sport” with cursing, tantrums and tirades that rattle line judges, throw opponents off their game and infuriate spectators. “Super Brat,” as the Brits nicknamed him, is just 21. 

“If I beat Borg in the finals,” he cracks to reporters, “it’ll be very hard to boo me.”

But did you know that Borg started out just the same way, a racket-tossing tyro facing a ban, as a teen, from Swedish tennis, where guys like him didn’t fit into “a gentleman’s sport?”

That’s the back-story we see in this film, mostly seen from Borg’s point of view. Bjorn Borg’s own son Leo makes a compelling brat himself, playing his dad as a kid who lets his temper beat him when the other player can’t.

He used the range-reducing two-handed backhand because he was also a teen hockey player, and his family gave up trying to tame his on-court behavior earlier than you would have liked.

But onetime Swedish star Bergelin (the always estimable Skarsgard) sees the inner fire and figures he can direct the conflagration. His first lesson? A practice where every shot the punk takes gets called “out.” Yeah, he reacts just the way McEnroe did. But he’s got to get that under control.

McEnroe’s intensity is summed up in his British hotel room. He calls the front desk, gets some magic markers, and paints his walls with the Men’s Singles Draw, marking off who each of them has to get through to make their date with history, in the finals.

Borg broods, dials himself into his training rituals, contemplates “escape,” lies about his identity to strangers like a man who cannot handle the screaming groupies that come with fame and bristles at everyone who calls him “a machine.” No, he is “a volcano, keeping it all in.” McEnroe sees this.  His coach remembers it. His fiance (Tuva Novotny) frets that he’s bottled it up for too long.

Meanwhile, Johnny Mac is obsessing over pinball machines, partying with “Broadway” Vitas Gerulaitis (Robert Emms, funny) and cutting the throat of his best friend on the tour, Peter Fleming (Scott Arthur).

On the court? Borg struggles against low seeds and McEnroe, whose nerves are more out in the open, gripes about English pigeons, curses umpires with the F-bombs TV audiences rarely heard and the infamous, “ExCUSE me? You cannot be SERIOUS!” which we did.

The final, with its soul-crushing passing shots, scorching, arcing serves and naked net-charging aggression, is pretty much what you’d hope for in a movie about this signal event in the sport. It’s not quite full speed, even with digital enhancements.

Skarsgard is one of the greatest character actors of his era and brings stoic pathos to the “those who can’t, coach” role. But Gudnason is the star here, and shoulders that responsibility about as well as Borg did.

Which leaves the movie to LaBeouf, who energizes scenes with his antic energy, his darting eyes prattle, letting us see that desire to be “the youngest ever” men’s singles champ and the deflating defeatism that sets in, only to be beaten back by sheer will and ego — the fear of being humiliated.

God help the LaBeouf haters out there, but this is a great performance.

There is suspense, even if you remember how the match turned out, in the surprising layers of back story and the touching coda.

There’s no blood on the mat, no referee counting down from eight. But “Borg vs. McEnroe” is a vivid reminder of the personal nature of this genteel combat sport, of a great rivalry and of a time when America, Sweden and the world were their most passionate about it.

MPAA Rating: R for language throughout, and some nudity

Cast: Sverrir Gudnason, Shia LaBeouf, Stellan Skarsgard, Tuva Novotny

Credits:Directed by Janus Metz, script by Ronnie Sandahl. A Neon release.

Running time: 1:47