Australian Open 2023: 7 biggest upsets from Week 1 ft. Rafael Nadal and Ons Jabeur

The first week of the 2023 Australian Open has finally rolled to a close, with upsets galore at Melbourne Park. While most of the players who were expected to win the championship have survived the initial few rounds, some have suffered unexpected losses at the hands of undistinguished opponents.

On the men's side, the top two seeded players have exited after just the second round, while a handful of seeded players on the women's side have been shown the door as well. With the third round currently underway, the Australian Open is very much living up to its billing.

Without further ado, here's a look at the five biggest upsets in Week 1 of the 2023 Australian Open:

#1 Mackenzie McDonald def. Rafael Nadal (Australian Open Second round)

Mackenzie McDonald beat defending champion and 22-time Grand Slam winner Rafael Nadal 6-4 6-4 7-5 in the second round of the 2023 Australian Open. Nadal showed plenty of discomfort late in the second set after picking up a hip injury, which seriously hampered his abilities during the encounter.

The Spaniard left for an off-court medical timeout and returned to the court to play out the set, fighting on valiantly, but ultimately was not fit enough to force a fourth set. Rafael Nadal's defeat came as one of the biggest upsets at the 2023 Australian Open, also marking his earliest exit from the event since 2016.

#2 Jenson Brooksby def. Casper Ruud (Second round)

Jenson Brooks reached the third round by defeating second seed and World No. 3 Casper Ruud for his first Top-3 win in his debut Australian Open. Brooksby scored the biggest win of his career by frustrating the two-time major finalist, with Ruud having to save three match points and battle back from 2-5 in the third set just to extend the contest.

Casper Ruud was one of the favorites to win the title going into the tournament. With the defeat, however, Ruud missed out on his chance to leave Melbourne as the top-ranked ATP player. Only Novak Djokovic and Stefanos Tsitsipas can now claim the World No. 1 spot by winning the Australian Open title.

#3 Alexei Popyrin def. Taylor Fritz (Second round)

Alexei Popyrin pulled off a shock win in front of his home fans

Cheered on by his home fans, Australia's Alexei Popyrin stunned World No. 9 Taylor Fritz, winning in five sets to advance to the third round of the Australian Open. The Australian wildcard scored a 6-7(4), 7-6(2), 6-4, 6-7(6), 6-2 victory against the eighth seeded Fritz to continue the trend in the early rounds of the competition.

The Top-10 win against Fritz was Popyrin's fourth overall and his second at a Major after his 2019 victory against Dominic Thiem in the second round of the Melbourne Major. Popyrin will face another American - World No. 89 Ben Shelton - for a place in the fourth round on Saturday.

#4 Markéta Vondroušová def. Ons Jabeur (Second round)

Second seed Ons Jabeur was knocked out of the 2023 Australian Open by former French Open finalist Marketa Vondrousova in the second round of the women's singles. It was also her first complete win over Jabeur in five meetings. Jabeur, who was the runner-up at Wimbledon and the US Open in 2022, came to Australia hoping to be a title contender but could not capitalize on the momentum.

Vondrousova will next face 17-year-old compatriot Linda Fruhvirtova, the youngest player left in the draw.

#5 Varvara Gracheva def. Daria Kasatkina (First round)

Seeded 8th at the Melbourne Major, Daria Kasatkina suffered a shocking loss in the first round to Varvara Gracheva in straight sets. The match lasted only 54 minutes, with Gracheva dominating all the way and winning 6-1, 6-1.

Kasatkina's best result at a Grand Slam tournament has been reaching the semifinals of the French Open in 2022 -- a yardstick she fell miserably short of. Up next, Varvara Gracheva will next face Karolina Pliskova in the third round.

#6 Zhu Lin def. Maria Sakkari

Zhu Lin, playing in the third round of a Grand Slam for the first time, is now into the last 16 at the 2023 Australian Open, defeating sixth seed Maria Sakkari 7-6(3), 1-6, 6-4 in an epic clash that lasted two and a half hours. The Chinese also claimed her first ever top 10 win in the process.

After losing the opening set, Sakkari came back well to take the second set and force a decider but Lin came out on top when it mattered most to push the Greek out of the competition. She is now the only unseeded player left in the top half of the draw and will face Victoria Azarenka in the next round.

#7 Sebastian Korda def. Daniil Medvedev

22-year-old Sebastian Korda earned the biggest win of his career on Friday, beating Daniil Medvedev 7-6(7), 6-3, 7-6(4) to reach the last 16 at the 2023 Australian Open.

The Russian's loss to Sebastian Korda guarantees a first-time finalist at the Australian Open from the top half of the draw. Medvedev has struggled for form since losing to Rafael Nadal from two sets up in the final 12 months ago and was simply outplayed by Korda, who began the season by reaching the final of the ATP event in Adelaide.

In the next round, Sebastian Korda will face Hubert Hurkacz for a place in the quarterfinals.