"Aleti", the working-class rivals to smarter Real Madrid, is the passion into which Gil pours huge quantities of his self-made fortune. One of his long-running feuds is with Ramon Mendoza, Real's supremo, whom Gil once accused of orchestrating a burglary at his country estate. "Whoever doesn't like Atletico in the lead," he said recently, "can die."
Gil, also the idiosyncratic Mayor of Marbella, has been constantly in trouble for his foul language and loutish behaviour. Spain's professional football league has banned him until February 1997 for punching a manager - a sanction he shows little sign of respecting.
In the 1993-94 season, when Atletico faced relegation, he called the Spanish football federation chief "a mafia boss, a cancer in the world of football", and described the Spanish referees' chairman as "a shepherd fit only to tend sheep and goats".
In 1990, Uefa, European football's governing body, banned him for two seasons for calling a French referee a homosexual. In 1991, the Spanish FA fined him pounds 16,400 for telling a referee he should visit a psychiatrist.
Last season, he racially insulted his own Colombian player Adolfo Valencia, threatening to "cut his black head off". He was "only speaking figuratively", a contrite Gil said when calmer. In the latest row, in April, he punched the manager of Compostela after a shouting match in which Compostela's owner said Marbella's voters "must be stupid".
Gil's belligerent style goes hand-in-hand with what former managers call his complete ignorance of football. "I might as well advise him on how to run Marbella," complained the Argentine Alfio Basile, who bowed out after four months in June 1995. Gil's current manager, the Serb Raddy Antic, broke records by surviving an entire season.
Gil, who gulps down eight fried eggs at a sitting, has in nine seasons devoured 20 Argentine, English and Spanish managers. Some lasted only days. One had a nervous breakdown. Another said the players, ruled by fear, walked a daily tightrope over a lake of crocodiles.
Jesus Gil, 63, was born in Burgo de Osma, 100 miles north-east of Madrid. At 17, he shared a boarding house with a priest and 19 prostitutes, keeping the establishment's accounts in lieu of paying rent. He mended gearboxes, then bought and sold lorries and eventually property.
In 1969, an apartment block he built in Segovia collapsed, killing 58 people. It had no plans, no architect and no surveyor, and the cement was barely set. He was jailed for criminal negligence for five years in 1971, but after 18 months the dictator Franco pardoned him. He borrowed money and started again, some say with an enduring chip on his shoulder.
Marbella, glitzy playground for rich Arabs and Russians, with possibly the densest concentration of powder-blue fringed suede cowboy boots in Europe, caught his fancy in 1979 when he attended a local weight-loss clinic. He homed in with his property deals with such disregard for the regulations that in 1988 the Socialist town council declared him persona non grata. His way round that was to stand for mayor. He created his Independent Liberal Group (GIL) party and won a landslide victory in 1991.
He promised to clear prostitutes off the streets and corral them into a purpose-built "whore-odrome", and adopted Franco's ruse of boosting public thermometers a degree or three to encourage tourists.
One night in August 1991, he descended upon Marbella's harbourside bars with his bodyguards and started haranguing the youngsters. "What a drink- sodden face you've got sonny," he bellowed. "How much have you spent on drugs today? You're dross and I'm going to get rid of you. Drunkards! Slugs!" Several people were injured in scuffles and a police car was burnt.
Gil's business deals have so prospered that he claimed last month to have lost all respect for money because he had "too much". He bought a mausoleum in Madrid's Almudena cemetery with a garden and room for 69 bodies, and favours the epitaph: "Here lies a brave man who laughed at imbeciles."
Fans of the Colchoneros ("mattress boys"), so-called for the red-and- white striped mattress-ticking that inspired Atletico's strip, don't mind the braggadocio. While Gil is on a winning streak, they love him.