Players in the Australian Open always must be ready to expect the unexpected. Because the tournament happens when many stars are potentially out of shape after a long offseason, the door is always open for upsets.

Upsets are at the heart of Australian Open tennis history. Read on to find out which of the most dramatic ones made our Betway Insider list of the all-time top 10.

Ranking the Top 10 Biggest Upsets in Australian Open Tennis History

  1. 2023 Men’s Second Round: MacKenzie McDonald defeats No. 1 Rafael Nadal

Match Result: 6-4, 6-4, 7-5

Young American MacKenzie “Mackie” McDonald was 27 years old by the time the 2023 Australian Open rolled around, and he was still searching for a signature win. A collegiate superstar at UCLA, McDonald had won the 2016 NCAA Division I title in both singles and doubles. Tennis fans had been waiting for him to break out as a pro.

McDonald drew an aging Rafael Nadal, the No. 1 seed, in the second round of the 2023 Australian Open. It was a minor miracle that McDonald still had legs at that point, because he had just needed five sets (and three lengthy tiebreakers) to beat fellow American Brandon Nakashima in the first round.

It didn’t matter: McDonald steamrolled Nadal in straight sets. It was the first time since 2016 that Nadal failed to reach the third round of a Grand Slam event.

  1. 2013 Women’s Quarterfinals: No. 28 Sloane Stephens defeats No. 3 Serena Williams

Match Result: 3-6, 7-5, 6-4

Despite all of her greatness, Serena Williams didn’t win the Australian Open every year she entered it. When she did lose, it was usually to heavyweights and familiar faces (Venus Williams, Kim Clijsters, etc.), but 2013 was a different story.

Fresh off 2012 victories at both Wimbledon and the U.S. Open, Williams cruised into the 2013 Australian Open quarterfinals without so much as even dropping four points in a set. In the tournament’s final eight, she was set to meet talented fellow American Sloane Stephens.

Stephens, just 20 and ranked No. 28 in the world at the time, fell a set behind. She then stunned both Williams and the tennis world by storming back to upset the legend. It’s fitting for her to be the first Australian Open women’s tennis underdog match winner listed here.

  1. 1989 Men’s Second Round: Ramesh Krishnan defeats No. 1 Mats Wilander

Match Result: 6-3, 6-2, 7-5

No. 1-ranked Mats Wilander was on top of the men’s tennis world heading into the 1989 Australian Open as the defending champion and winner of three 1988 Grand Slam events. The Swede struggled in the first round against unseeded compatriot Tobias Svantesson before facing India’s Ramesh Krishnan, an unseeded player, in the second round.

Krishnan, a three-time Grand Slam event quarterfinalist, was no slouch. However, his straight-sets upset of Wilander was certainly a surprise.

  1. 2002 Men’s First Round: Alberto Martin defeats No. 1 Lleyton Hewitt

Match Result: 1-6, 6-1, 6-4, 7-6 (7-4)

The stars had finally aligned for Australian Lleyton Hewitt by 2002. He had emerged as the world’s No. 1-ranked player after a signature victory at the 2001 U.S. Open and was looking to become the first native son to win the Australian Open since the 1970s.

Things appeared to be on schedule for Hewitt in the opening round as he cruised to a 6-1 first-set victory over unseeded Spaniard Alberto Martin. That would be the end of Hewitt’s journey, because Martin took the next three sets and vanquished the top seed.

In all fairness, however, it must be noted that  Hewitt was battling chicken pox during the tournament.

  1. 2005 Men’s Semifinals: No. 4 Marat Safin defeats No. 1 Roger Federer

Match Result: 7-5, 4-6, 7-5, 6-7 (6-8), 9-7

Roger Federer was on top of the world in 2005. He was:

  • The reigning Australian Open champion
  • The reigning Wimbledon champion
  • The reigning U.S. Open
  • The world’s No. 1-ranked player

Coming off a three-set sweep of Andre Agassi in the Australian Open quarterfinals, Federer was due to face Russia’s Marat Safin in the finals. Safin had lost to Federer in the 2004 Australian final in a swift, three-set affair. Safin gave Federer a far more intense battle in 2005, as four out of the five sets required the winner to take at least seven games.

Safin secured a late break to defeat Federer 9-7 in the final set, knocking the Swiss legend off his pedestal.

  1. 2003 Women’s First Round: Marlene Weingartner defeats No. 3 Jennifer Capriati

Match Result: 2-6, 7-6 (8-6), 6-4

Former American world No. 1 Jennifer Capriati had quite an up-and-down professional career. She remarkably made the semifinals at the French Open as a 14-year-old (not a typo) in 1990, then made two more Grand Slam event semis in 1991 before going a 10-year drought at majors.

Turning her career around in 2001, Capriati won that year’s Australian Open and French Open, as well as the 2002 Australian. She returned to Melbourne in 2003 as a two-time defending champion.

And then she hit another down in her career -- losing to unseeded German Marlene Weingartner in the first round of her quest for the 2003 women’s Australian tennis championship.

  1. 2001 Women’s Final: No. 12 Jennifer Capriati defeats No. 1 Martina Hingis

Match Result: 6-4, 6-3

We just mentioned here that former American tennis star Jennifer Capriati had a lot of ups and downs during her career. One of those upswings came in the form of her surprising 2001 Australian Open championship,

Along the way to her title, Capriati defeated three-time Australian Open champion Monica Seles in the quarterfinals, world No. 2 Lindsay Davenport in the semifinals, and world No. 1 Martina Hingis in the final. Her win over Hingis came in straight sets.

Just how good was Hingis at the time Capriati stunned her? The Swiss star was making her fifth straight Australian Open finals appearance -- having won three of them. She certainly wasn’t expecting to lose to Capriati, and Capriati probably wasn’t expecting to beat her:

"I just couldn't believe it," Capriati said. "I got the chills. I just thought, `Wow, the moment has finally come. Now I can enjoy it.'"

  1. 1976 Men’s Final: Mark Edmondson defeats No. 2 John Newcombe

Match Result: 6-7, 6-3, 7-6, 6-1

En route to his unlikely 1976 Australian Open title, unseeded Australian Mark Edmondson defeated No. 5 seed Philip Dent, top-seeded Ken Rosewall, and No. 2 seed John Newcombe. Not only was Edmondson unseeded prior to the tournament, but he was astoundingly ranked No. 212 in the world, making him the lowest-ranked player to win a Grand Slam event in the history of the ATP rankings.

Edmondson never even made it to another Grand Slam event final during his career. However, he remains a noteworthy historic figure as the most recent Australian man to win an Australian Open singles title.

  1. 1984 Women’s Semifinals: No. 9 Helena Sukova defeats No. 1 Martina Navratilova

Match Result: 1-6, 6-3, 7-5

Prior to her semifinal meeting with Helena Sukova at the 1984 Australian Open, American tennis superstar Martina Navratilova was riding a stunning 74-match winning streak (an Open Era record). During that span, Navratilova won both the 1984 U.S. Open and Wimbledon titles. She also came into her match with Sukova as the reigning Australian Open champion.

Somehow, the ninth-seeded Czech ousted Navratilova after dropping the first set. Navratilova couldn’t have been too devastated by the loss, because she proceeded to win the next four Grand Slam events that she entered. Had she won the 1984 Australian Open, Navratilova would have won seven straight major championships. Unfortunately, she fell victim to the second-greatest Australian Open upset of all time.

  1. 2017 Men’s Second Round: Denis Istomin defeats No. 2 Novak Djokovic

Match Result: 7-6 (10-8), 5-7, 2-6, 7-6 (7-5), 6-4

What was the most shocking men’s Australian Open result in the tournament’s history? It had to be the time that the greatest Australian Open tennis player of all time fell in the second round despite being at the height of his career.

“Better than (winning) my first title,” said Denis Istomin, describing how he felt after stunning Novak Djokovic in the second round of the 2017 Australian Open. When he lost to Istomin, Djokovic was a two-time defending Australian champion who would go on to win four more titles between 2019 and 2023.

Djokovic, a 10-time tournament champion, never seemed to lose in Australia… except when he faced Istomin in 2017.

Parameters of Rankings

These rankings are based on the performances of each underdog player involved, each defeated player’s tennis legacy, the unexpected nature of each upset, and the match’s significance in Australian Open history.

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