Australian Ajla Tomljanovic was too much for American tennis legend Serena Williams.

After over three hours of play, the match ended with a ball in the net by Williams.

Tomljanovic prevailed over the 23-time grand slam winner, 7–5, 6–7 (4–7), 6–1, in what may have been Williams' final match.

Ahead of the US Open, Serena Williams has signaled that she plans to retire from tennis after the tournament.

- These are happy tears, she says from the center court.

Thanks sister

A teary-eyed Serena Williams thanked her family to a standing ovation at Arthur Ashe Stadium.

Among others, older sister Venus Williams:

- I wouldn't have been Serena if Venus didn't exist.

She is the only reason Serena Williams exists at all.

On the night of Friday, Williams and her sister Venus withdrew from the doubles tournament.

The Williams sisters together have 14 grand slam titles in doubles, including two US Open titles, in 1999 and 2009. In addition, they have won three Olympic gold medals together in doubles.

- I tried but Ajla simply played a little better, says Williams about the night's meeting.

Wiliams led in the first set 5–3 when Tomljanovic managed to turn around and take the set.

The second set also began with Williams leading, 4–0, before Tomljanovic came back and tapped in.

The set was finally decided in a tiebreak which Williams took home.

In the third set, the star never really had a chance.

Next up is the Russian Ljudmila Samsonova for Tomljanovic.

"Best ever"

It wasn't just Williams who was emotional.

The 29-year-old Australian more or less apologized for winning.

- I'm really sorry, because I love Serena as much as you do.

What she has done for me and for the sport is absolutely incredible.

I could never have believed when I was little and saw her play, that I would get to meet her.

This is a surreal moment for me, says Tomljanovic.

- She is the best of all time.

Point.

CLIP: Here's Serena Williams' incredible career

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Here's Serena Williams' incredible career