For the second year in a row, royal sisters-in-law Kate, the Duchess of Cambridge, and Meghan, the Duchess of Sussex, stepped out together for the Ladies' Singles Final at Wimbledon.

And for the second year in a row, the pair watched Meghan's close friend Serena Williams compete in the final, vying for her 24th Grand Slam title.

Duchesses Kate and Meghan watched from the royal box Saturday as Williams took on seventh-seed Simona Halep. Williams lost the final in straight sets, 6-2, 6-2.

(MORE: Duchess Kate reveals Prince George received lesson from favorite tennis player Roger Federer)

"She couldn’t be a better friend to me," Williams said of Meghan in a press conference Wednesday following her semifinal win. "Low moments, high moments, she’s always there and that’s all I want to be to her."

(MORE: Duchesses Kate and Meghan take kids to watch Princes William and Harry play polo)

Saturday also marked the second Wimbledon appearance this year for both Kate and Meghan.

The Duchess of Sussex made a surprise appearance at Wimbledon last week to watch Williams win her second round match. That visit drew some controversy over allegations of extra tight security around the duchess, who sat with friends in the members' section.

Kate, patron of the All England Lawn Tennis and Croquet Club, also visited Wimbledon last week, watching a British player compete and visiting the practice courts and warm-up area.

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Saturday's appearance at Wimbledon is the second joint outing this week for Kate and Meghan.

PHOTO: Kate, Duchess of Cambridge and Meghan, Duchess of Sussex chat watch the women's singles final match between Serena Williams of the U.S. and Romania's Simona Halep on day twelve of the Wimbledon Tennis Championships in London, July 13, 2019.
Ben Curtis/AP
Kate, Duchess of Cambridge, left, and Meghan, Duchess of Sussex chat as they sit in the Royal Box on Centre Court to watch the women's singles final match between Serena Williams of the U.S. and Romania's Simona Halep on day twelve of the Wimbledon Tennis Championships in London, July 13, 2019.

The pair stepped out, with their kids in tow, on Wednesday to watch their husbands, Prince William and Prince Harry, play a charity polo match.

PHOTO: Simona Halep of Romania plays a backhand in her Ladies' Singles final against Serena Williams of the U.S. during Day twelve of The Wimbledon Championships in London, July 13, 2019.
Ben Curtis/Getty Images
Simona Halep of Romania plays a backhand in her Ladies' Singles final against Serena Williams of the U.S. during Day twelve of The Wimbledon Championships in London, July 13, 2019.
PHOTO: Serena Williams serves to Romania's Simona Halep during their women's singles final on day twelve of the 2019 Wimbledon Championships in Wimbledon, southwest London, July 13, 2019.
Toby Melville/AFP/Getty Images
Serena Williams serves to Romania's Simona Halep during their women's singles final on day twelve of the 2019 Wimbledon Championships in Wimbledon, southwest London, July 13, 2019.

Meghan was a newlywed last year when she sat courtside with Kate for the Ladies' Singles Final, in which Williams lost to Angelique Kerber. Williams and her husband, Alexis Ohanian, were guests at Harry and Meghan's May 2018 wedding in Windsor.

PHOTO: Meghan, Duchess of Sussex, and Pippa Middleton in the Royal Box ahead of the final Wimbledom match between Serena Williams of the U.S. and Romania's Simona Halep in London, July 13, 2019.
Hannah Mckay/Reuters
Meghan, Duchess of Sussex, and Pippa Middleton in the Royal Box ahead of the final Wimbledom match between Serena Williams of the U.S. and Romania's Simona Halep in London, July 13, 2019.

Kate is a longtime tennis fan and a tennis player. She told guests at Wimbledon last week that eight-time Wimbledon winner Roger Federer, also a semifinalist in this year's tournament, is the favorite player of her 5-year-old son Prince George.

PHOTO: Catherine, Duchess of Cambridge, arrives for the Women's Final at the Wimbledon Championships at the All England Lawn Tennis and Croquet Club, in London, July 13, 2019.
Pool/Reuters
Catherine, Duchess of Cambridge, arrives for the Women's Final at the Wimbledon Championships at the All England Lawn Tennis and Croquet Club, in London, July 13, 2019.

She also said the superstar has even played tennis with George, which Federer said took place at Kate's parents' home in Bucklebury.

PHOTO: Catherine, Duchess of Cambridge meets junior players ahead of the Women's Final on day twelve of the 2019 Wimbledon Championships in Wimbledon, southwest London, July 13, 2019.
Victoria Jones/AFP/Getty Images
Catherine, Duchess of Cambridge meets junior players ahead of the Women's Final on day twelve of the 2019 Wimbledon Championships in Wimbledon, southwest London, July 13, 2019.

Kate and Prince William plan to attend the Men's Singles Final Sunday at Wimbledon, according to Kensington Palace.