Australia's Sam Stosur has said goodbye to singles tennis in typical fashion — it wasn't easy, but there was no questioning her commitment, and she gave her home crowd plenty to cheer about.

In the end, however, Stosur bowed out at Melbourne Park, bringing to a close a two-decade singles career with a tough 6-2, 6-2 loss against Russia's Anastasia Pavlyuchenkova on Kia Arena.

The 37-year-old has gathered affection and respect for her performances over the years as one of Australia's most successful women's tennis players, but there has also been a level of frustration with a sense of opportunities not taken.

While the Australian Open has not been a happy hunting ground, in singles at least — going into this year's tournament, Stosur had only reached the third round in singles in the last decade — she chose Melbourne Park to make her singles bow.

The Brisbane-born, Gold Coast native made her professional debut as a 15-year-old in 1999.  

She quickly became known for her focus on training and fitness, and a solid game featuring the kick-serve, sliced backhands, power forehands and inside-out shots to the corners to set up points.

Her power gave her an advantage — although this would be blunted in recent years as more and more players added power to their games. Sometimes, however, there were question marks over the mental side of Stosur's approach and her lack of consistency in being able to finish off matches.

Her undoubted physical fitness was tested in 2007 and 2008 as she had to deal with Lyme's disease, forcing her to miss eight months of tennis.

But she returned to tennis and climbed the rankings, cracking the world's top 10 in 2010.

Her play on clay was particularly impressive — she made the semis at Roland Garros on four occasions, getting to the final in 2010.

Stosur went in as favourite, having ended Justine Henin's 24-match winning streak in Paris in the round of 16, then won a tough three-setter against Serena Williams before sweeping through a semi-final against Jelena Jankovic, against whom she lost just three games.

But having shown what she was capable of in the tournament, and holding the top record on clay for the season with 20 wins and two losses going into the final, Stosur was undone by the performance of Francesca Schiavone.

The Italian 17th seed dominated at the net, and a combination of a few too many unforced errors from Stosur and a string of winners from her opponent allowed Schiavone to clinch victory in straight sets.

The loss could have been a real stumbling block for the Australian, but although she failed to get past the third round in Paris the following year, Stosur would find her groove on the hardcourts of Flushing Meadows.

Stosur beats Serena and US Open crowd

The signs were good when she beat second seed Vera Zvonareva in the quarters, then was taken to three sets by future world number one Angelique Kerber in the semis.

In the final she faced Williams, who was looking for her fourth US Open title.

Stosur held her nerve, controlling her fierce forehands, holding serve and putting Williams under huge pressure. She broke twice in the opening set, and then in the first game of the second set came the key moment.

Stosur had Williams at break point, but the American produced a forehand for an apparent winner, letting loose a cry of "come on".

But because Stosur managed to get to the ball, even though she couldn't get it back in play, the umpire gave her the point, judging that Williams had verbally hindered the Australian's ability to complete the point.

The Flushing Meadows crowd matched Williams's anger at the decision and began to boo Stosur,  but after giving back the break the Australian steadied and proved too strong for Williams. 

Her victory cemented her place as one of Australia's best women's players.

She is one of only six Australian women to win a grand slam singles title in the Open era since 1968, the group also includes Margaret Court, Evonne Goolagong Cawley, Chris O'Neil and Ash Barty.

Stosur would reach a peak ranking of number four in February 2011, and she maintained a top-10 ranking for more than three years ending in 2013.

In a time when Australian women's tennis is dominated by world number one, Ash Barty, it is worth remembering that Stosur was the top-ranked Australian female player in world tennis for nearly nine years, between 2008 and 2017.

Although some tennis fans and pundits may look at Stosur's career and see missed opportunities, she has spent more than 20 years on tour and won nearly $US20 million ($27.6 million) in prize money.

Her international career saw Stosur represent Australia in the final of the Fed Cup in 2019 — 16 years after her debut in the event — and when she went to the Tokyo Olympics last year, she became the first player to represent Australia in five Olympic Games in tennis.

There has been good news off the court in recent years, with Stosur becoming a mother in July 2020, when her partner, Liz Astling, gave birth to a baby girl.

Rather than leave things open, Stosur last month revealed on social media her plans to end her singles career at Melbourne Park.

After a two-and-a-half-hour, first-round epic against American Robin Anderson, Stosur could not back up against the 10th-seeded Pavlyuchenkova, losing 6-2, 6-2.

This is not retirement for the Australian, who will continue to play doubles tournaments in 2022.

The pair showed last year what they could achieve with an unexpected women's doubles title at the US Open. Stosur also reached the mixed doubles final at last year's Australian Open with Matt Ebden. 

But regardless of what lies ahead, Stosur's record over more than 20 years deserves appreciation, not just for what she has won or the way she has played, but what she has meant to many upcoming Australian women's tennis players over the years.

“She's an Australian champion, plain and simple. She has set the tone for us Aussies as tennis players for years and years," Ash Barty said before the tournament.

Those in the crowd on Kia Arena certainly showed Stosur their love and appreciation after her loss to Pavlyuchenkova.