The table was set for a moment of family triumph. Venus and Serena Williams were dressed and seated for the grand occasion on Sunday night, and Will Smith, who had played their father Richard with uncanny similitude in the movie “King Richard,” was poised to win the Oscar for best actor.

But then, as so often happens with the Williamses, things got complicated — and, through no fault of the sisters, an evening that should have affirmed their against-great-odds rise to stardom instead became about Smith slapping the comedian Chris Rock onstage.

When Smith accepted the Oscar, he delivered a tearful, rambling, semi-apologetic speech in which he said that “art imitates life” and “I look like the crazy father, just like they said about Richard Williams.”

Serena, watching the speech from a front-row box seat, covered her face with her hand.

Unexpected and uncomfortable to watch, Smith’s failure to control his temper or rise to the occasion turned the night into one that the Williams sisters will never forget, for all the wrong reasons.

It has often played out like this for these remarkable siblings, with moments of triumph tempered by controversy or mixed emotions.

Smith said of the man he played onscreen: “He was a fierce defender of family.” On Monday, he apologized to Rock, the Williams family and the Academy of Motion Picture Arts and Sciences, calling his actions “unacceptable” and “inexcusable” and saying that “violence in all its forms is poisonous and destructive.”

“We don’t know all the details of what happened,” Richard Williams, via his son Chavoita LeSane, told NBC News. “But we don’t condone anyone hitting anyone else unless it’s in self-defense.”

Richard Williams, complex and frequently difficult to read, certainly created some of the friction and misunderstandings with the wider world. But, as “King Richard” makes clear, he and Oracene Price — they divorced in 2002 — also laid the groundwork for one of the biggest success stories in sports, and for two incandescent tennis careers who have lasted far longer than one would have imagined considering that neither Venus nor her younger sister Serena had much choice in the matter of their career path.

The sisters were raised from birth to be tennis champions, with Richard Williams’s 78-page plan as the blueprint and plenty of help from coaches like Rick Macci, who for four years in the early 1990s polished the sisters’ strokes and tactics and provided the seed capital and the support that helped make the long-shot family dream a reality.

Macci said he saw Richard Williams, now 80, at his home in West Palm Beach, Fla., about three months ago and received a visit from him with a documentary crew about a month ago at his tennis academy in Boca Raton, Fla., where the sisters once trained. Macci said Williams was diminished after two strokes, but that they were still able to exchange stories.

“There have been a smorgasbord of things that have played out through the years: the good, the bad, the ugly,” Macci, who figured prominently in “King Richard,” said in a telephone interview on Monday. “I think when you’re at the top and you’re unique, or two of a kind in their case, you’re just going to have speed bumps along the way. Last night was just unfortunate because it was just such a celebration of a story that you just cannot make up and unfortunately now that slap is the story. And the story should have been this miraculous thing.”

Some of the speed bumps were bumps of a different sort. In 1997, Venus Williams made her first major impact at a Grand Slam tournament, reaching the final of the U.S. Open at age 17 with white beads in her hair and thunder in her strokes.

“I’m tall; I’m Black,” the 6-foot-1 Williams said early in the tournament. “Everything’s different about me. Just face the facts.”

But her breakthrough took on another dimension when she and the Romanian player Irina Spirlea bumped into each other on a changeover during their semifinal. In defeat, Spirlea suggested that Venus Williams had an arrogant attitude, while Richard Williams talked about the racism his family had faced on tour and labeled Spirlea a “big, tall, white turkey.”

In 2001, the family came to Indian Wells, Calif., and was booed by the crowd after Venus Williams withdrew from her semifinal match against Serena Williams shortly before it was to begin because of an injury. There was speculation at the time that Richard Williams was predetermining the results of his daughters’ matches — speculation that the Williamses denied — but the late withdrawal sparked suspicion and upset spectators. When Serena Williams returned to the court for her final against Kim Clijsters, with Richard and Venus in the stands, there were boos throughout the match, and Richard and Venus said they heard racial slurs from some fans.

Serena won the title, but triumph again had a bitter taste. She boycotted the tournament for 14 years, returning in 2015, with Venus ending her 15-year boycott the following year.

Even without controversy, the sisters’ dual success has been intricate. Remarkably close in their youth, as they remain today, their rise to the top of the game meant that they became frequent opponents, and though Venus Williams was the first to reach No. 1 and the first to win Wimbledon in singles, Serena Williams would prove, as her father predicted, the greater player, winning 23 Grand Slam singles titles to Venus’s seven.

Venus handled being usurped with grace, and Serena has always made it clear that she would never have become the champion she did without Venus as her role model and cheerleader-in-chief.

“Venus wasn’t at all resentful,” Macci said. “She’s never been like that. And Serena has always looked up to Venus as ‘my big sister’ and even today, they have that. That’s very uncommon. You’re not keeping score, because it’s family and if one wins, we both win. I saw that early on.”

It has worked beyond even Richard Williams’s imaginings. Though he predicted greatness and No. 1 rankings for Venus and Serena, he had long maintained that they would retire relatively early to pursue other interests. Instead, they have endured and excelled while pursuing other interests, including interior design and fashion design. Though they are near the end now and have not played on tour since last summer, they remain un-retired. Venus Williams is 41. Serena Williams is 40.

Sunday night would have been a time to revel in the length of their journey, the depth of their achievements and Richard’s legacy. Instead, it turned into a night for Serena to cover her eyes, but, cinema, even when it is an Oscar-winning true story, won’t be the last word on the Williams sisters, or their father.