Serena Williams walked onto Arthur Ashe Stadium with her diamond-encrusted dress glittering under the New York sky, over 23,000 people screaming their approval.

Poor Danka Kovinic, her opponent, must have felt like the loneliest woman at the US Open.

"We love you Serena," fans screamed as the 23-time Grand Slam title winner appeared for what could have been the final singles match of her career.

This being New York, there were no limits to the hype or expectancy.

"THE GREATEST OF ALL TIME" screamed the courtside videos followed by "#Twirl for Serena", a plea to mimic the player's signature victory celebration.

Anybody who was anybody wanted a piece of history.

Tennis legend Martina Navratilova, nursing her pet dog, sat next to heavyweight boxing legend Mike Tyson.

There was former US president Bill Clinton, Hollywood star Hugh Jackman, Vogue editor Anna Wintour and fashion designer Vera Wang.

Williams's outfit caught the eye, a six-layer skirt --- one tier for every US Open title she has won --- and a diamond-encrusted bodice.

"It is a dress made for a supernova's farewell," said The New York Times.

As Kovinic sat patiently courtside, actress and rapper Queen Latifah narrated a showreel of Serena's greatest moments.

"Queen of this, this and this. Queen of style, queen of grace. You rewrote history, page after page."

Serena hasn't officially committed to retiring but Queen Latifah appeared to know better.

"If you decide to return, the throne will be waiting. The queen of our hearts."

Film director Spike Lee, a regular at Flushing Meadows, got one of his most cherished close-ups helping with the pre-match toss.

But it wasn't just the glitterati who were out in force on Monday.

Loyal fans of Williams had travelled far to witness what could have been the icon's last appearance.

Tia Green had jetted in from Oklahama City and along with her four cousins from Indiana, explained what Williams meant to them.

"For minorities, she's an ambassador. She showed you can do things you thought you couldn't do," the 55-year-old African-American woman told AFP.

"For a little girl from Compton, California and to play with her sister and be able achieve what she has achieved is a great inspiration, that you can do anything you put your heart to, no matter whatever the circumstances."

All five women wore bright T-shirts with the slogan 'Unapologetic greatness, GOAT'.

Green observed the sprawling tennis complex and saw another impact of the Williams' legacy.

"You can see the diversity in the crowd. Ten, 20 years ago, this place didn't look like this."

Another fan, born in Beirut and a citizen of the US since 1999, Olmazah from Queen's watched the match eight rows back.

Her ticket was bought for her by her daughter. Together they held up a banner with the words: "Thank you King Richard for queen Serena" in honour of the player's father and coach.

From her vantage point, the dream was being kept alive as Williams shook off a plague of double faults to take the first set.

"It's a dream come true to see her here at last," said Olmazah who only gave one name.