Serena Williams lost to Canadian tennis player Bianca Andreescu in the U.S. Open final, missing her chance to tie for the most Grand Slam singles title wins ever.

The 19-year-old Andreescu beat the 37-year-old Williams 6-3, 7-5. It is the first Grand Slam title for a Canadian player and the first singles title win ever for a woman making her debut at the U.S. Open, according to the U.S. Open.

O Canada 🇨🇦



Bianca Andreescu becomes the first Canadian to win a Grand Slam singles title.#USOpen | #WomenWorthWatching pic.twitter.com/naCBhTSaAL — US Open Tennis (@usopen) September 7, 2019

Among those who watched the match at the USTA Billie Jean King National Tennis Center in Queens, New York, was Williams' close friend, the former Meghan Markle, the Duchess of Sussex, sister Venus Williams, filmmaker Spike Lee and Vogue editor-in-chief Anna Wintour.

It was the fourth straight loss for Williams since returning from childbirth in 2017.

She played some of her best tennis in the first set after being broken in the opening game, reported NBC Sports. She unraveled in the second before battling back from 1-5 down.

The Arthur Ashe Stadium crowd, more than 20,000, became so loud that Andreescu covered her ears.

Williams first made her U.S. Open debut in 1998 when she was 16, making it to the third round, according to the U.S. Open. She won her first Grand Slam title a year later when she beat Martina Hingis.

Williams lost last year's finals to Naomi Osaka and was embroiled in controversy when she got into several confrontations with chair umpire Carlos Ramos.

During the game, Ramos issued three penalties against the athlete for allegedly receiving coaching, smashing her tennis racket and for verbal abuse when she called Ramos a "thief" and accused him of stealing a point from her.

In an essay for Harper's Bazaar in July, Williams — who gave birth to her daughter, Alexis Olympia Ohanian Jr, a year before the 2018 U.S. Open finals — said she felt "defeated and disrespected" by Ramos and thought it took a "triumphant moment" away from Osaka.