NEW YORK — Back when Serena Williams, then 16, and Venus Williams, then 17, played each other on tour for the very first time, at the Australian Open in January 1998, no one possibly could have known it would start a series that would last for two decades.
Actually, Serena did sort of predict it.
"What you guys saw today," she said after losing to Venus way back then, "is definitely something in the future to watch for."
Well, here we are: Williams vs. Williams, Part 30.
When the two sisters meet in the third round of the U.S. Open on Friday night at Arthur Ashe Stadium, it will be their earliest Grand Slam matchup since that initial one 20 years ago. And across their tremendous journeys in tennis, through all of the victories and the trophies and the weeks at No. 1 in the WTA rankings, they've done it together.
Each set a standard for the other to strive for.
Each also helped the other during practice sessions and pep talks.
"I know when I play her, I have to play some of my best tennis. She does, too. It propels us to continue to play that for the tournament. It sets a tone for us," said Serena, who'll turn 37 in less than a month.
"I feel like throughout our career, we have pushed each other to be the best that we can be," she added, "and be Venus and Serena Williams."
Their story is certainly unique. And one that's still worth marveling at.
Two kids from one household, growing up to rule their sport. Serena owns 23 Grand Slam singles titles; Venus has seven. Both have been ranked No. 1. They also ushered in an era of women's tennis featuring a power-based style, built on big serves and groundstrokes, along with enviable court coverage, that transformed the game.
"Obviously, they have been holding the torch for a long time. Venus and Serena have been incredible advocates for our sport and, yes, they inspire so many," U.S. Fed Cup captain Kathy Rinaldi said, adding that "a lot of credit goes to them" for the rise of younger American stars such as Sloane Stephens, the 2017 champion at Flushing Meadows, and Madison Keys, last year's runner-up.
On top of it all, they transcended their sport, becoming cultural icons and fashion trendsetters, and have also spoken out about issues to help others — from Venus' advocacy for equal prize money in tennis to Serena's recent discussions of her health scare during childbirth and postpartum depression.
"It's incredible what they've done. I mean, amazing, really. Obviously there's been other siblings that have had fantastic careers in tennis, but none anywhere close to what they've managed to achieve," three-time major champion Andy Murray said. "I'd be surprised if anything like that ever happens again."
On the court, Serena leads their head-to-head series 17-12. She leads 10-5 at Grand Slam tournaments.
They grew accustomed — as did the world — to seeing them meet for all-in-the-family major finals, nine in all, with Serena ahead 7-2 in that category, too.
So a Week 1 showdown seems a tad anticlimactic.
Said Venus: "I mean, obviously, it's early in the tournament."
Said Serena: "We would have rather met later."
"I'm sure they will hate it — both of them hate this — but I think it's going to be beautiful for tennis," said Victoria Azarenka, a two-time Australian Open champion who lost to Serena in two U.S. Open finals.
The all-Williams title match at the 2001 U.S. Open , the tournament's first women's final in prime time, was the first Grand Slam final between two sisters since the 1800s. Venus won that one; Serena won their rematch in New York a year later.
"Unfortunately, and fortunately, we have to play each other. We make each other better. We bring out the best when we play each other. It's what we do," Serena said. "I think we're used to it now."