In the brutal world of professional boxing, there is little room for sensitivity or self-doubt. Which makes World Boxing Council super-bantamweight champion Israel Vázquez a fascinating case study in man's dual nature. In the ring Vázquez is a predator who has battered and bloodied the world's toughest 122-pound fighters over the past four years with piercing jabs and vicious left hooks.

But when he puts down the gloves he is an unassuming, solicitous husband who sweeps up the floor at his wife's hair salon in South Gate, Calif., before driving her and their two sons to their modest three-bedroom house in Huntington Park. As a fighter Vázquez is a merciless avenger who, after losing his crown to Rafael Márquez last March, reclaimed it in August by opening an inch-long gash under Márquez's right eye and then pummeling him with jaw-jolting hooks until the referee stopped the fight in the sixth round. But as a family man Vázquez is so protective of his close relatives that he considered retiring in March because of their distress over his grotesque appearance after Márquez shattered his nose.

Vázquez first exhibited this duality as a child in Mexico City. "He was always well behaved at home and studious in school," says his father, Valentín, who raised the future champion and his three older siblings in a cramped two-room apartment attached to the funeral home where Valentín sold coffins and dressed corpses. But young Israel also had an explosive temper. "He dreamed of becoming a soccer star," says Valentín, "and when he injured an ankle during his first soccer game and could no longer play, he smashed the foot against a wall over and over, yelling, 'my foot is useless!' "

Hindered by weak ankles, Vázquez took up boxing instead. He trained intensely, rising at 5 a.m. every morning to get in an hour of roadwork before school and then working out in the gym for two-and-a-half hours each afternoon after classes. In the ring he was no less ruthless as a teenager than he is now, as his amateur record of 58 consecutive knockouts (with no losses) suggests.

When he turned pro at 17 the baby-faced Vázquez immediately established a reputation as an anvil-fisted headhunter by breaking his first opponent's nose in the first round. Two years later he started turning scouts' heads when he knocked out the highly touted and, until then, undefeated Oscar Larios in the first round in Mexico City. "I couldn't believe it," says Larios. "When I woke up my gloves and sneakers were off. I had been out for five minutes."

The following winter Vázquez got a call from Los Angeles-based fight manager Frank Espinoza, who was intrigued by the constant reports from his contacts in Mexico City about the 20-year-old banger with the crushing left hook. Espinoza got Vásquez a work visa and helped set up his first fight in the U.S., against a hapless palooka with a 2--14 record in El Cajon, Calif. Nervous and overzealous, Vazquez fought poorly, going down briefly in the third round but coming back to record an uninspiring six-round win. The Top Rank talent scout on hand to evaluate Vázquez suggested that Espinoza put him on the next flight back to Mexico City. "This guy has no defense," the scout said. "He'll be a club fighter at best."

But Espinoza was impressed by Vázquez's pluck in hanging in for the victory. He convinced the dispirited fighter to sign with him and move to Los Angeles. Vázquez arrived penniless and unable to speak a word of English, but eager to prove himself. He spent his first four months in the country living with Espinoza and the next nine months sharing a room with future super-flyweight champion Martín Castillo, a fellow Mexican, at a Ramada Inn a few blocks from the South El Monte gym where they trained.

Vázquez struggled to cope with life as a Mexican immigrant in Los Angeles. "I felt so lonely and depressed," he says. "In Mexico I had always hung out at home with my family. I was never much of a partygoer. Here I didn't really have anybody."

Until, that is, he met a pretty Mexican hairstylist named Laura Díaz, who worked in the hair salon run by the wife of his trainer, Manuel Robles. "After I saw her there the first time, I kept going back to get my hair cut until I asked her out," Vázquez says. They were married in 2002.

Vázquez's climb up the super-bantamweight ranks was torturously slow, and he was forced to supplement his meager boxing income with house-painting jobs he obtained through Robles's son. "The $3,000 to $5,000 I made in fight purses every four months or so didn't last very long," he says. In May 2002, after a disheartening 12-round loss in his second encounter with Larios, Vázquez hit rock bottom. "My career had stalled," he says. "I decided to make a change."

He started working out at the Wild Card Boxing Gym in Hollywood with elite trainer Freddie Roach and honed his skills by sparring regularly with super-featherweight champion Manny Pacquiao of the Philippines. Roach was impressed by Vázquez. "He's a humble, polite, hardworking fighter," says the trainer. "He trains six days a week year-round, fight or no fight."

In the spring of 2004, six years and 22 fights after he had emigrated from Mexico, Vázquez's dedication finally paid off. He captured the International Boxing Federation's super-bantamweight title with a decisive beating of José Luis Valbuena. Soon afterward Vázquez signed with Sequan Promotions and cashed in his $50,000 bonus to buy Laura her own hair salon.

But the following November, two weeks before the most important fight of his career -- a third encounter with Larios, for the WBC super-bantamweight title -- Vázquez's world was turned upside down when his two-year-old son, Israel Jr., was diagnosed with hemophilia, a rare disorder that prevents blood from clotting properly. "It was the most traumatic moment of my life," he says. "We found out that anytime he gets hit or bruised he can bleed internally. We have to monitor him constantly, and we have rushed him to the hospital 12 times in the past two years to be injected with a coagulant." Last fall, with Israel Jr. interned in the hospital and Laura days from giving birth to their second son, Vázquez anxiously shuttled between the gym and the hospital.

But on fight night in Las Vegas, he caught a huge break. "I believe in God, and with his help things eventually worked out," says the fighter, who opened up a nasty two-inch gash over Larios's left eyebrow with a blistering combination in the third round. The wound wouldn't close, so Larios was forced to cede the title to Vázquez.

The victory boosted Vázquez's marketability, and with Oscar De La Hoya's Golden Boy Promotions on board as co-promoter he was able to command six-figure purses. His next two fights, high-voltage and blood-soaked victories over Iván Hernández and Jhonny González in 2006, enthralled his rapidly expanding fan base.

Vázquez's aggressive style makes for great theater, but his weak defense is a cause for concern. He was knocked down twice by González before he stormed back to win the fight with a 10th-round TKO. "Israel gets hit too much," says Roach. "He doesn't move his head enough. He's vulnerable to uppercuts."

It was an uppercut that splintered Vázquez's nose in the second round of his first bout with Márquez, last March at the Home Depot Center. The two fighters faced off for 21 furious minutes, trading thunderclaps until Vázquez's gruesomely deformed nose was so clogged by loose cartilage and clotted blood that he was forced to quit in his corner at the close of the seventh round.

After that fight, Vázquez waved off Roach's public appeal that he take the rest of the year to recover from the punishment he had sustained. (The fighter and the trainer subsequently parted ways.) Vázquez sought out a Beverly Hills specialist who reconstructed his nose, and the rematch with Márquez was on for Aug. 4 in the border town of Hidalgo, Texas.

Vázquez-Márquez II had all the elements of an instant classic: a blistering pace, a blood aplenty, dramatic two-way action, skillful execution, a knockdown, and a gem of a third round in which the fighters squared off and traded blows without pause. Vázquez finally prevailed in the sixth round, delivering nearly two dozen unanswered hooks that left Márquez dazed on his feet and prompted the referee to stop the fight. The victory brought Vázquez's record to 42-4.

The rubber match is set for March 1, but this time Vázquez, emboldened by his stunning comeback, says he'll do more than finish Márquez off. After the bout the 30-year-old fighter plans to move up to fight Venezuela's Jorge Linares at 126 pounds and eventually take on Paquaio or Márquez's brother, Juan Manuel, at 130 pounds. "God willing, I will make my own historical footprint," Vázquez says. "I want to become the fourth Mexican in history to win three championships in three weight divisions."

Judging by the difficulties he's surmounted thus far, both inside and outside the ring, he'll probably do just as he says.

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