There are the titles Venus and Serena Williams amassed, the cultural forces they became, the records and firsts they rang up. But like most great champions, the numbers hardly tell the whole story. Perhaps the most wildly impressive aspect of the Williams sisters’ careers was their so-called “Sister Act” was never an act.

From the time they hit the scene to the night they inaugurated the US Open’s first primetime women’s final in 2001 to their last years together on tour, Venus and Serena not only changed the game and the world around them -- but nothing ever seemed to fray their relationship with each other.

What we saw from them instead over the quarter of a century -- including Thursday night at the US Open in a first-round doubles loss and Friday in Serena's final match --  was a bond that was unbreakable, a closeness that was never faked, a comical ability to always make the other laugh, an unshakeable loyalty and laudable lack of jealousy.

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There’s simply no overstating how much Venus paved the way for Serena, especially in their formative years, even though they were born just 15 months apart. Each of them turned pro at the age of 14, within a year of each other between 1994 and 1995. Their father, Richard, labeled them both “Ghetto Cinderellas” because they grew up playing amid the occasional sound of gunfire in Compton, California, before moving to Florida to train.

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His strategy of holding them back from junior tennis as they honed their games in practice against each other was just one of his many unorthodox moves, along with leaving the training of Venus and Serena to himself and Oracene Price, their mother. But look how it all worked out.

Venus roared to her first US Open final in 1997 as an unseeded 17-year-old, and she won the first of her five Wimbledon titles three years later after defeating Serena in a semifinal match. They were still learning how to manage their conflicted feelings about playing each other then, and the showdown was less memorable for the quality of tennis than the booming power they brought to the court.

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As amazing as they already were individually, there was still just something different, bigger, bolder, about seeing them on the court together, often as teammates, but more often against one another blistering groundstrokes, handling the other’s best shots and sending some sizzling back. What an incalculable advantage for both of them to spend their adolescence practicing against the other future best player in the world.

No women back then played power tennis like the Williams sisters did, but they’ve had a generation of imitators since. Venus covered the court with her long legs and snared shots that no one else got with her telescopic reach; Serena was already fierce and strong, remorselessly driven and lightning fast to the ball.

That Wimbledon semifinal was our first high-stakes glimpse of how the predictions about the Williams sisters really were about to come true, and their fortunes were going to be almost cruelly entwined. One of them would win, one of them would have to lose. But after Venus prevailed on that first occasion -- on a Serena double fault, of all things -- a clue arrived regarding the mystery of how they’d handle all that was to come.

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When they met at the net, Venus, whose celebration had been muted, leaned in toward her little sister and gently whispered in her ear, “C’mon. Let’s get outta here.”

AN ARRAY OF SPORTS SIBLINGS has spoken over the years about the psychodrama of having to compete against each other. But none of them were also simultaneously, realistically vying for No.1 in the world -- not to mention doing so in the intimate confines of an individual sport. Nor did the others have to shoulder the weight of being groundbreaking icons and racial standard-bearers. Venus and Serena were the first female African American women to win a Grand Slam major in the Open Era and the first Black women to reach No.1 since Althea Gibson dominated amateur tennis in the 1950s after breaking the color barrier in the sport.

Navigating all of that for two-and-a-half decades in public life should be seen as a victory as remarkable as all the Williams sisters’ 48 Grand Slam singles, doubles and mixed doubles titles combined. As Billie Jean King says, “Venus and Serena Williams transcend tennis and have ushered our sport into the 21st century.

"From the first time I saw them in 1988 at a World TeamTennis clinic, I knew they were special, and they have both led tennis with grit and grace. They don’t look like the tennis establishment, and they brought a style of play that focused on power and passion. Even with all their championships, their greatest contribution, in and out of tennis, will forever be opening doors for others, particularly people of color.”

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Venus and Serena had an uncanny ability to adjust on the fly as their individual stature in the game shifted, even when Serena overtook Venus for No.1 in the world and never looked back. They continued to share a house together for years. Once on tour, they often flew together, ate together, practiced together and roomed together even on the nights before they played for tennis’ biggest titles.

They’d wake up, go to the tournament, dress for the final in the same otherwise deserted locker room, walk on and off the court together, and after the match, there were usually flowers waiting for the winner when they returned to their room. “Can you imagine doing all that?” Carlos Fleming, Venus’ longtime agent, once marveled.

Serena eventually outpaced Venus by a significant margin in most career numbers, including Grand Slam titles singles (23 to 7), a gap that began widening even before Venus was diagnosed with Sjogren’s syndrome in 2011. It’s only natural to wonder how many more majors Venus would’ve amassed if she didn’t come along at the exact same time as the best tennis player in history -- no gender qualifier needed. Even Roger Federer endorsed the idea, ceding GOAT honors to Serena in a 2018 interview.

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Serena defeated Venus in seven of their nine Grand Slam tournament finals. On the seven more occasions in which they met in an earlier round of a major, the winner went on to win the championship another four times. (Venus once, at the 2000 Wimbledon Championships.)

That means, all told, 12 of Venus’ Grand Slam title runs were thwarted by her sister in the 20-year span that Venus was still advancing to at least one of the four major finals. Venus played her last in 2017 at the Australian Open. That was also the same year Serena was off the tour most of the time after giving birth to her daughter, Olympia.

FOLKS FROM ALL walks of life -- sports writers to academicians to weekend hackers -- have tried to capture the multifaceted significance of the Williams sisters, knowing it has been immense. Millions of words have been spilled dissecting and reflecting and remarking on their unique journey as athletes, women and business moguls.

While their impact is often compared to the effect Tiger Woods had in golf, that yardstick fails in one glaring respect: All three of them are African Americans in predominately white sports who unlocked new ideas of what’s possible, but far more people of color have followed the Williams sisters into women’s tennis -- especially at the top level -- than materialized in golf after Woods came along.

A few years ago, Venus herself provided perhaps the best look at how she and Serena made their parallel lives as sisters and tennis champions work in a 2016 essay she wrote for "The Players’ Tribune." It shouldn’t be a surprise that such an original take would come from her.

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Venus has seemed like an old soul from the moment she appeared on the WTA Tour at the Bank of the West tournament in Oakland, California, where she made her pro debut at 14. She was still gangly and wet behind the ears. She already stood 6-foot-1 and would later jokingly compare her appearance to “a baby giraffe.” She was already bracingly smart. When asked if she agreed with the projections that she was destined to become a superstar, she said, “I'm prepared to face failure because I know that before you become successful, you fail."

Then she added a kicker: “I think I have the game to beat anyone. I'm not going to say I can't. I can't just accept [someone else] is better” -- all sentiments that both Williams sisters stuck to like a mantra throughout their careers.

“Not your day?” a reporter asked Venus after she lost the 2000 Sony Ericsson Open final.

“I don’t ever feel like it’s not my day,” she volleyed back.

What made Venus’ "Player’s Tribune" essay so notable was it felt like the first draft of an epilogue, even though she and Serena still had many years left to play. And it was Venus’ words. Not somebody else’s.

Also, what Venus chose to reflect on wasn’t the same thing that others do -- namely, how in the world did she and Serena navigate the passing of the torch between them? Instead, what Venus essentially inferred is we’ve been framing it wrong. We should all look instead at what being in position to exchange the torch meant. Once upon a time, for a very long time, a Williams was the best damn tennis player in the world.

For me,” Venus wrote, "being the big sister meant that when I made my professional debut, I was the only player on tour who looked like me. I was the only player with my skin color, with my hair, with my background, with my style. … When I became world No.1 in 2002, I wasn’t just World No.1. I was also the first Black American woman to reach No.1. And it meant that I had to carry with me the importance of what I had accomplished. And I was honored to do that.

Being the big sister meant that when my little sister made her professional debut, I became a lot of new things to her -- her colleague, her competitor, her business partner, her doubles partner. But I was still, first and foremost, the one thing I had always been: her family. I was her protector -- her first line of defense against outside forces. And I cherished that.

It was yet another lesson from the Williamses on sisterhood. What others saw as the eclipse of one sister by another, Venus and Serena saw as the ultimate victory. They had both made it. And they did it the best way possible. Together.