With the fourth round of the Australian Open in the books, it's time to highlight which players are on the rise and which ones look most vulnerable heading into the final three rounds of the tournament. Players who have been eliminated are of little interest to fantasy players as the tournament unfolds, so this column is meant to take a look ahead based on what's happened so far rather than reflect on the past.
An exciting men's draw has come down mostly to the usual suspects, though a few surprise upsets have occurred and more may be yet to come. Novak Djokovic and Rafael Nadal continue to mow down the competition despite injury concerns of varying levels, and three Russians are still vying to bring home the country's first men's singles Grand Slam title since Marat Safin won here in 2005. All told, six of the top eight seeds remain, while the other two guys are squaring off with a semifinal berth on the line. The women's draw has been more wide open, though four former Grand Slam champions, including each of the top three seeds, remain. At least one American woman is guaranteed to make the semifinals, as two of the three remaining will go head-to-head. Both draws have underlying storylines of a new crop of stars trying to push out the legends of old, but while the top young women have already reached the pinnacle of the game, their male counterparts are still in search of the breakthrough against an old guard that has refused to be brought down.
Novak Djokovic - After his ability to continue the tournament was thrown into question by an injury suffered in the third round, Djokovic not only soldiered through but looked relatively comfortable in a 7-6 (4), 4-6, 6-1, 6-4 fourth-round win over Milos Raonic. The No. 1 seed occasionally clutched at his side and seemed unable to execute the forehand down the line at his customary level, but the rest of Djokovic's game seemed normal against Raonic. Even at less than 100 percent, the eight-time Australian Open champion is the clear favorite to at least make the final in a top half of the draw that looks substantially less intimidating than the bottom half. If he can take care of Alexander Zverev in the quarterfinals, Djokovic would be left facing a much less accomplished opponent in the semis.
Andrey Rublev - Rublev has never won a set in three previous meetings with fellow Russian Daniil Medvedev, and while Medvedev is the clear favorite against his compatriot – and perhaps the favorite to win the whole tournament – Rublev has to fancy his chances better this time than ever before. Thanks to a much-improved serve to go with arguably the best forehand in the world, the seventh-seeded Rublev has steamrolled his way into the quarterfinals without dropping a set. The fourth-seeded Medvedev has more variety and big-match experience, but the court surface is playing very fast this year, which favors Rublev's all-out aggression over Medvedev's methodical tactics. At the very least, expect Rublev-Medvedev IV to be the most competitive bout yet between the two next-gen stars.
Stefanos Tsitsipas - Tsitsipas got a walkover into the quarterfinals when Matteo Berrettini was forced to withdraw due to injury, but even that edge in freshness likely won't be enough to overcome the uphill battle that awaits him. The No. 5 seed's quarterfinal opponent will be Rafael Nadal, who is yet to drop a set in this tournament and owns a 6-1 career head-to-head edge against Tsitsipas. Nadal, by the way, is vying for his 21st Grand Slam singles title, which would break his current tie with Roger Federer for the most all time among men. Should Tsitsipas somehow find a way through Nadal, he would be the underdog against the Rublev-Medvedev winner, and a win in that match would likely lead to a clash with Djokovic in the championship match. While it feels like only a matter of time before the 22-year-old Tsitsipas breaks through for his first Grand Slam title, it almost certainly won't be here and now.
Aslan Karatsev - After breezing through the first three rounds, Karatsev showed an impressive combination of fitness and mental fortitude in the Round of 16, erasing a two-set deficit to outlast 20th-seeded Felix Auger-Aliassime 3-6, 1-6, 6-3, 6-3, 6-4. The man Medvedev described as "Russia's secret weapon" absolutely wallops the ball off the ground, and Karatsev's chances of continuing his Cinderella run were boosted when No. 18 seed Grigor Dimitrov upset third-seeded Dominic Thiem in the Round of 16. Dimitrov's no slouch himself and will be the favorite in his fourth career Australian Open quarterfinal (he's 1-2 in the first three), but Karatsev certainly looks capable of upsetting a third consecutive seeded opponent after knocking out No. 8 seed Diego Schwartzman and Auger-Aliassime in his last two matches.
Naomi Osaka - Osaka faced two match points against Garbine Muguruza in the Round of 16 but found a way to win, escaping with a 4-6, 6-4, 7-5 victory. Having gotten through that tough draw, the title favorite will be an extremely tough out moving forward. Unseeded quarterfinal opponent Su-Wei Hsieh will provide some stylistic challenges for Osaka given her unconventional game style, but a lack of rhythm shouldn't keep Osaka's excellent serve and groundstrokes from overpowering Hsieh on this fast hard-court surface. Anything short of her fourth title in the last six hard-court Grand Slams played should be viewed as a disappointment for Osaka.
Simona Halep - Halep got revenge on Iga Swiatek in the Round of 16, avenging her loss at 2020 Roland Garros with a 3-6, 6-1, 6-4 win, which incidentally snapped Swiatek's 10-match Grand Slam win streak. The No. 2 seed and two-time Grand Slam champion has a game style that seems better suited to slow conditions, but Halep is a proven performer on all surfaces. Quarterfinal opponent Serena Williams has a 9-2 edge in their career head-to-head, but they have only clashed twice since 2016, and their most recent meeting was a stunning 6-2, 6-2 Halep upset in the 2019 Wimbledon final on a fast grass surface. While Serena is always capable of stepping up in big matches, Halep has looked more impressive over the past few days and should enter this high-profile matchup as the favorite.
Karolina Muchova - Muchova is entering her prime at age 24 and announcing her presence as a contender on the game's biggest stage. She's yet to drop a set through four rounds, coming back from 5-0 down in the second set of her third-round 7-5, 7-5 victory over sixth-seeded Karolina Pliskova before following that effort up with a 7-6 (5), 7-5 win over in-form No. 18 seed Elise Mertens. The No. 25 seed will be the underdog in the quarterfinals against Australian No. 1 seed Ashleigh Barty, who's yet to drop a set herself, but with all the pressure on Barty, Muchova should put forth a formidable upset bid.
Jessica Pegula - While No. 22 seed Jennifer Brady will be the favorite in the All-American quarterfinal clash with Pegula, the unseeded Pegula's on an extremely impressive run and shouldn't be counted out. The 26-year-old Buffalo native has premier wins over No. 12 seed Victoria Azarenka in the first round and No. 5 seed Elina Svitolina in the Round of 16, and she lost just four games over her other two matches combined. Additionally, Pegula won the only previous head-to-head meeting against Brady, 7-6 (5), 6-4 at the Cincinnati Masters in 2020. That win is significant considering it came during Brady's breakout in the latter half of 2020, and the fast hard-court conditions in Cincinnati represent a close comparable to how the courts are playing at this tournament.