Serena Williams defeated in third round of US Open

Capping off an iconic career, Serena Williams thanked everyone who has "been on her side" for decades after losing in the third round of the US Open on Friday night.

Stepping off the court after falling to Ajla Tomljanović in three sets, Williams was crying as the crowd in the stadium cheered for the superstar who revolutionized the sport.

"These are happy tears," Williams said during an on-court interview.

She thanked her family and said she was grateful for her parents and her sister, Venus Williams, as well as her husband, Alexis Ohanian, and their daughter Olympia who is frequently at the matches.

Looking back at her career, Williams said it was the "most incredible" journey she has been on in her life.

"I'm just so grateful, because yeah, you got me here," Williams said to the crowd.

On her plans to move away from tennis, she said she didn't think she would play any more matches, but added, "but you never know."

Serena Williams, the 23-time grand slam singles champion considered by many to be the greatest of all time, played what likely is the final professional tennis match of her career on Friday night at Arthur Ashe Stadium.

Since losing her professional debut in September 1995, Serena Williams has become the most dominant force in women's tennis in the last 30 years.

Together with her older sister Venus, the Williams sisters transformed the sport, making a regular habit of winning grand slams in both singles and doubles tennis.

Serena has won at least 73 career singles titles, 23 doubles titles and two mixed doubles titles, which includes 39 grand slam titles: 23 singles titles, 14 doubles titles and two mixed doubles titles.

She is one singles grand slam title behind the all-time record held by Australian Margaret Court.

When asked by CNN's Christiane Amanpour earlier this year if she still wanted to beat Court's record, she replied: "I should have had it, really, I should — I've had many opportunities to have it. But I'm not giving up, to answer your question."

She addressed this later in Vogue, saying:

The four-time Olympic gold medalist has won over $94.5 million in career prize money, more than any other female athlete.

Away from the court, Williams announced her engagement to Reddit co-founder Alexis Ohanian in 2016, and gave birth to their daughter, Alexis Olympia Ohanian Jr., in 2017.

Read more about her career and remarks on evolving from tennis here.

CNN's Jill Martin contributed reporting to this post.

Serena Williams has lost her US Open singles match to Australia’s Ajla Tomljanović at Arthur Ashe Stadium.

The defeat likely means the end of her storied career. After winning 73 career singles titles and 39 Grand Slams, Williams said earlier this year she will “evolve away from tennis” after this tournament. 

In a match that lasted a little more than three hours, Tomljanović defeated Williams 7-5, 6-7(4), 6-1 to advance to the round of 16.

Serena Williams' coach, Rennae Stubbs, spoke to ESPN's Pam Shriver at the beginning of the third set. Williams lost the first set and had to fight her way to winning the second set in a tiebreaker.

Stubbs credited Williams' opponent Ajla Tomljanović, saying she is handling the crowd gracefully and playing a respectable match.

"She's digging so, so deep today, and Ajla is playing unbelievable. I have to give so much credit to Ajla, she's handling this crowd, she's handling this moment. What we're seeing why Serena's so great," Stubbs said.

Serena Williams forced a decisive third set against Ajla Tomljanović, winning the second set 7-6 (4). The third set is underway with Tomljanović serving.

Williams had raced to a 4-0 lead in the second set. But Tomljanović battled back, breaking Williams in the fifth game. She later held off a fervent Williams’ push, as the 23-time major singles champion failed to break the Australian to close out the set in a lengthy game at 2-5.

And then, with Williams serving for the set, Tomljanović broke to put the set back on serve.

The set went to a tiebreak, which Williams won 7-4.

The winner of this third-round match will face Russian Liudmila Samsonova in the round of 16.

Serena Williams and Ajla Tomljanović are playing a tiebreak for the second set. The winner is the first player to 7 points and winning by 2 points.

Williams is leading the tiebreak 4-3.

Fans inside the stadium are anxious after Ajla Tomljanović battled to get back on serve in the second set. At one point, Serena Williams was leading the second set, 4-0.

Williams is now leading 6-5 with Tomljanović serving.

The crowd is on its feet as Serena Williams takes the lead in the second set.

Fans are high-fiving each other, punching the air and screaming, not wanting this to be her last match.

Earlier in the set, someone yelled “You’ve got this, Queen!” from the back of the stadium.

Serena Williams' husband, Alexis Ohanian, is in the stands wearing a shirt showing a photo of their daughter, Olympia.

Olympia attended her mom's first- and second-round matches at the US Open.

Many observers noted that Olympia wore her hair in braids with white beads – the same hairstyle her mother famously sported in 1999 when she won her first grand slam tournament in New York.