When the actor Thomas Hulce was preparing to play the film role that defined him, “Amadeus,” he read about Mozart, but he truly studied the tennis star of the day, John McEnroe. Who better to model a precocious brat of a composer on than the player the world nicknamed “SuperBrat?”

“I’m a vulgar man,” Hulce’s Mozart admits in the film, “I assure you my music is not.”

The McEnroe analogy is almost too obvious.

When filmmaker Julien Faraut was plumbing the archives of French sport for a documentary about Gil de Kermadec, the government cinematographer charged with capturing close-up footage of every year’s French Open Tennis Championships in the ’70s and ’80s, he found reels of every great players of the era — Borg, Vilas, Connors and Lendl. And he found reel upon reel of John McEnroe.

Kermadec was putting together instructional films out of this footage, and was drawn to the fiery American with the most complete game ever seen, an artist and “perfectionist” who railed at those he perceived as less perfect (line judges, chair umpires), and at the courtside distractions. Chief among those distractions? Kermadec’s admittedly noisy Arriflex high speed (for slow-motion) camera and the filmmaker himself, sitting court side with a huge microphone, holding up “slate” cards behind McEnroe indicating date, reel, etc.

Faraut took that footage, filmmaker Jean-Luc Godard’s declaration that “Cinema lies, sport doesn’t” and the theories of French film critic Serge Daney — that tennis is inherently cinematic, with drama and players who, like filmmakers, control time — and created a mesmerizing, brilliant film about the movement, motivation and mentality of McEnroe at his peak.

“John McEnroe: In the Realm of Perfection” is quite simply the greatest tennis film ever made and one of the finest documentaries to honor any sport.

Actor Mathieu Amalric (“The Diving Bell and the Butterfly”) narrates this exploration of one player’s game, letting us see up close and in slow motion “what the human eye cannot.” With Kermadec’s rare, unseen footage, we catch a perfectionist in his moment, a player who thrived with an “unpredictable” game that was “never about violence, but variety.” And we come to understand what so transfixed that cinematographer long ago, and something of the McEnroe mystique that lingers over the game even today.

A cinema camera, Faraut argues, creates a “form of truth” about sport, and in Kermadec isolating his camera, focusing in 3/4 view solely on McEnroe throughout a match, we see just “what is needed to win a point in a tennis match” — the speed, agility, snap-judgments, hand-eye coordination, sprints and slides, gasping stamina and mental acuity involved.

We get all that just from watching McEnroe, up close, candid, in his element and in his best year — at the 1984 French Open finals at Roland Garros Stadium.

Faraut plays around with documentary form in what is, in essence, a “found footage” film conjured out of another’s work. He uses vintage tennis instructional movies, live action and animated, an archived TV essay on McEnroe by tennis journalist Bud Collins, that clip from “Amadeus” and tight, fascinating dissections of McEnroe’s play and his endless arguments with officials and swipes at cameramen (including Kermadec himself).

The arguments are a revelation. McEnroe used them to “control time” in his matches, a piece of gamesmanship that still seems grossly unsportsmanlike and unfair, all these decades later.

But his gripes — the sometimes blown calls, the damned noisy cameras in the pristine mid-point silence at Roland Garros, and the disconcerting Frenchman with the huge boom mike sitting behind him? The brat had a point.

“Perhaps I’m 20 times better at seeing, 20 times better at hearing than you ever WILL be,” he berates one chair umpire.

You can write it off to nostalgia for the game when “the rackets were of wood and the men of iron,” but Kermadec’s footage underlines that point as well. Today’s game might have no room for a brittle McEnroe, who hated to practice and used doubles as his match-prep, who never cooperated posing for photos and could not always bend his pursuit of perfection to conditions on the court. Tennis today has no head case to match McEnroe, nobody with as perfect a drop shot or cunningly-disguised surprise lob, either. It’s all about big rackets and baseline power now.

Faraut has made a great film about a sporting icon,  but one that also serves his original purpose, paying tribute to a cinematographer who “studied tennis the way other filmmakers study Emperor penguins in the Antarctic.” Which is to say, McEnroe isn’t the only one “In the Realm of Perfection” here. 

MPAA Rating: unrated

Cast: John McEnroe, Gil de Kermadec, narrated by Mathieu Amalric

Credits:Directed by Julien Faraut, . An Oscilloscope Labs release.

Running time: 1:35