Venus and Serena Williams' childhood tennis coach has an amazing story about coaching them for the first time

Though Venus and Serena Williams have ruled the tennis world for years, their beginnings were more modest than many professional tennis players.

As discussed in ESPN's Alyssa Roenigk's oral history of Serena's path to winning 22 majors, the Williams sisters' tennis careers began in a park as their parents taught them the game in hopes of winning tournament money down the line.

After holding them out of many amateur events until they were ready to go pro, in 1991, the Williams looked into hiring a professional coach.

The search led them to Rick Macci, who spoke to Roenigk and told a fantastic story about meeting the Serena and Venus and coaching them at a park in Compton, California, for the first time.

"They picked me up in a Volkswagen van," Macci said. "It was shaking back and forth, three months' worth of McDonald's wrappers, clothes, Coke cans, bottles and a spring coming out of the seat. We get to the courts, and it's not a country club. It's a crummy park. There are guys playing basketball, people passed out in the grass, broken glass all over the courts, people drinking beer."

Macci said when the sisters, who were around 11 and 10 years old at this time, began hitting, he wasn't terribly impressed. Only when he made it a competition, did the lights suddenly turn on.

"Usually after five minutes I can tell if there is something special. We're hitting balls, and I'm going, 'These girls aren't that good.' There were arms and hair and legs flying everywhere, beads flying out of their hair. They were improvising, hitting off their back feet. Then I said, 'Let's play some points.' I swear to God, their stock went soaring through the hemisphere. Their footwork got better, their prep got better, they cleaned up their act. What blew me away was their burning desire to run and fight and get to every ball like their hair was on fire. I had never seen two kids try so hard. I had never seen bodies that could move like that. Athletes with their body types went to other sports; they didn't play tennis."

Serena's sister Lyndrea told ESPN that Serena wasn't just a natural at the game, she was naturally athletic, too.

"Even as a kid, Serena was built. She was so muscular. She didn't have to do a lot of work to get that physique. It was an anomaly that she was gifted at 3 years old to have that body. I remember thinking, wait 'till they get a load of you."

Of course, the rest is history, as Serena and Venus won the Fed Cup debut in 1999. Since, Serena has won 22 majors and is pursuing her 23rd this season, while Venus has won seven majors. While Macci helped the two sisters improve, it sounds like the desire to succeed was always there.