Serena is to play in a diamond-encrusted outfit for the rest of her run at the US Open ©Getty Images

Serena Williams has started her final tennis tournament in diamonds, with the American great given a customised encrusted outfit by Nike for her swansong at the US Open.

Williams won in straight sets in the first round yesterday against Montenegro's Danka Kovinić 6-3, 6-3 and is to return tomorrow to face Anett Kontaveit from Estonia, the second seed.

If successful, she will play in the third round of the women's singles against Evgeniya Rodina or Australian Ajla Tomljanović.

The 23-time Grand Slam winner still has a chance to equal the record of Australian Margaret Court in her last competition, who won 24 during her career.

During her match against Kovinić, Williams wore a figure skating-style dress, emblazoned with diamonds.

The skirt had six layers - a nod to her six women's singles titles at Flushing Meadows - the first of these coming in 1999 when she was 17.

Nike provided a matching jacket and bag, as well as special edition NikeCourt Flare 2 shoes, which feature 400 hand-set diamonds, created alongside Serena Williams Jewelry.

Her sister Venus Williams is competing in the first round today as a wildcard, with her first opponent being Alison Van Uytvanck from Belgium.

Iga Świątek, the world number one from Poland, finally met one of her idols Williams, weeks after paying tribute to her.

In a press conference at the National Bank Open, the 21-year-old said she hoped Williams had heard of her and that they could play each other before the American's retirement.

The pair can only meet in the final of the US Open, as they are drawn on opposite sides of the bracket.

Players went to watch Williams' first match of the tournament, including fellow American Coco Gauff.

Other celebrities such as former United States President Bill Clinton, director Spike Lee, singer Gladys Knight, actor Hugh Jackman, boxer Mike Tyson and fashion journalist Anna Wintour were in attendance too.

Twitter celebrated her last tournament with hashtags #Serena, #SerenaWilliams and #ThankYouSerena, which shows an emoji of a goat playing tennis.