Venus Williams was just 17 years old when she played in the first tennis match against the woman who would soon become her greatest on-the-court rival: her sister, Serena Williams, who was only 16 when the two met at the 1998 Australian Open.

Venus won that match in straight sets, then won the rematch that followed later that year at the Italian Open. From that point on, the sisters took the tennis world by storm, revolutionizing the game and taking home an unprecedented number of championships and trophies. Combined, they have won 122 singles titles, including 30 Grand Slam singles titles, and earned over $175 million in prize money. And while they’re considered rivals on the court, they’re actually very close — together, they’ve won 22 doubles titles as teammates, 14 of which have been in Grand Slam competitions.

The Williams sisters have dominated the tennis world for decades. You can chalk a fair amount of it up to preternatural talent, but had it not been for the dedication of their father, Richard Williams, and their disciplined childhoods, they probably wouldn’t have ever played tennis at all.

Channel-surfing convinced Richard to turn his daughters into tennis champions

Richard never had any interest in tennis until one day, sitting at home in Long Beach, California, he caught a broadcast of the prestigious French Open. It wasn’t the act of hitting a ball back and forth on a clay court that caught his eye, nor was it the incredible athleticism and determination of the competitors that made him sit up. Instead, it was the prize money — $40,000 to the tournament winner — that piqued his interest.

From that point forward, Richard decided that he’d raise champion tennis players, no matter what it took. He had stepchildren from his wife Oracene’s previous marriage and he taught them the game, but it was clear that he’d have a better chance of molding his and Oracene’s younger daughters, Venus and Serena, into world-class athletes.

Locals recall Venus and Serena holding tennis rackets in their strollers as their parents played in the early 1980s, learning the game so they could pass it on to their daughters. Richard had been a football player in Shreveport, so he had athleticism and discipline that made him a quick study.

Venus got her first real lessons when she was just 4 years old. Serena tagged along and was soon begging to play, too. The young sisters hardly ever left the courts, grinding through practice sessions that started as early as 6 a.m. and stretched into the dark of night after school was out. They sometimes had to return 500 volleys just to earn a rest for the evening.

Eating up all that court time didn’t come without its complications or sacrifices.

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Venus and Serena Williams in 1998

Venus and Serena began their tennis educations in Compton

Shortly after Venus was born, the Williams family moved to Oracene’s hometown of Saginaw, Michigan, which is where Serena was born in 1981. They returned to California a few years later and wound up in Compton, a working-class neighborhood that was plagued with drugs and violence throughout the 1980s.

Gangs tended to control the local parks and tennis courts, which were generally rundown and dilapidated. Richard often had to argue with and even fight gang members in order to get court time — and early on, the fights didn’t tend to go his way, leaving him with broken ribs and 10 teeth knocked out of his skull. After a while, though, Richard willed himself to victory over those who would stop him from turning his girls into champion athletes.

"It had taken two years and almost destroyed my body and my spirit,'' Richard wrote in his 2014 memoir. "But in that moment, none of that mattered. What mattered was the courts were ours."

Not only did Richard win, some gang members even began to serve as unofficial security guards during the long, grueling father-daughter practice sessions. In 2015, he told CNN that at one point, white children who were bussed in to play on the courts began shouting at his daughters. Gang members who were watching the taunting implored him to step in, but Richard just watched as it happened.

“When (they) came to me and said, 'You can't talk to Venus in that way ... I said, 'Watch out. I'm going to do what I want to do,’” he recalled. “Criticism is one of the greatest things, I think, that we've been trained to live through."

They outlasted every obstacle, distraction and danger, including gunshots that would ring out as they worked on their own blistering serves. They weren’t the target, but it was still terrifying for a couple of kids.

"At first, I just thought someone was setting off firecrackers or popping some balloons, but once I learned what the sound meant it would shake me up pretty good," Serena wrote in her 2009 autobiography, Queen of the Court.

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Serena and Venus in 2017

A move south allowed the Williams sisters’ talents to blossom

In 1991, the Williams family moved to Florida so that Venus and Serena could train full-time. It was already obvious that the young tennis prodigies were destined for great things. They were recruited to the Palm Beach area by a coach named Rick Macci, who saw early on that they had remarkable potential. When Venus and Serena weren’t training with Macci, they were playing at local courts — again, rundown and fractured, though there were no gang members this time.

“What blew me away about Venus and Serena was the burning desire,” Macci told the Palm Beach Post in 2017. “Almost like ‘I got to get every ball, I’m not letting anything get past me.’”

Even as they trained with professionals, Richard was tough on his daughters, demanding more out of them every day.

“Half the time he wouldn’t want new balls, he would use bad balls so the girls would have to run faster and bend lower,” Macci recalled. “He’d throw a beer bottle in the back of the court just so there’d be broken glass.”

Neither Williams sister competed in a tournament until they went pro, eschewing the tradition of moving through the junior ranks. But they went pro remarkably early — Venus turned pro first, at just 14 years old, in 1994. Serena followed a year later.

The rest is history — and their original hometown is keen to commemorate it. In November 2016, the sisters traveled to back to Compton (well, technically East Rancho Dominguez Park, as their old neighborhood was incorporated on its own) to have their old courts, now entirely rebuilt, named in their honor.