The singles action switches exclusively to Rod Laver Arena on Tuesday - here is our preview of four intruiging quarterfinal clashes.
Su-wei Hsieh  vs Naomi Osaka 
The Japanese third seed is aiming to extend her unbeaten record in major quarterfinals as she takes on the 35 year-old who is best-known as one of the WTA Tour’s most difficult opponents due to her quirky shot selection. Osaka has the upper hand, winning four of the pair’s five prior encounters. Still, Hsieh has the tools to push the 23 year-old to the brink, having taken a set off Osaka on four of those occasions. “My mind can’t fathom the choices she makes when she’s on the court ... it’s not fun to play, but it’s really fun to watch,” said Osaka of the match-up. By becoming the oldest player to make a Grand Slam quarterfinal debut in the Open Era, Hsieh has already exceeded her own expectations. Despite joking that Osaka will probably “smash” her, the veteran will approach their clash buoyed with by the experience of toppling seeds in big moments, having notched 8 career top-10 wins including one last week over Bianca Andreescu.
Serena Williams  vs Simona Halep 
Into the final eight at a Grand Slam for a record-equaling 54th time, Williams knows not to read too much into her 9-2 head-to-head advantage over the Romanian since that lead narrows to 3-1 at majors. Front of the American’s mind will be tactics to avoid the emphatic defeat she suffered in their most recent face-off, when Halep won the 2019 Wimbledon final 6-2 6-2. “I think Simona played the perfect match. It's going to be a different process for her because she knows she can play like that against Serena, which she never did before,” said Williams' coach Patrick Mouratoglou. The second seed, who is prepared for Williams’ power punches, reiterated her belief that no two matches are the same. “I need my best tennis to win against her,” said Halep, a finalist here in 2018. But 39 year-old Williams enters this showdown on a mission – to reach her 40th major semifinal, a round in which she’s unbeaten in eight prior visits.
Novak Djokovic  vs Alexander Zverev 
The German has two wins against the eight-time defending champion and has a strong chance of snapping his drought of eight straight losses to top 10 opponents at Grand Slams. Djokovic has spent roughly two-and-a-half hours more on court than his younger opponent and dropped four sets through the first four rounds – the most of any of his prior journeys to major quarterfinals. Still, the Serb is familiar with the taste of success down under, and is on a ten match winning streak against top 10 opponents at the Australian Open, with his last such loss coming at the hands of Stan Wawrinka in the 2014 quarterfinals. 33 year-old Djokovic survived a three-set test against Zverev, a decade his junior, during the ATP Cup earlier this month and is expecting grueling rallies. “He moves very well for his height, his size, but he's also one of the best servers we've got in the game,” mused Djokovic. “He’s a complete, all-around player.”
Grigor Dimitrov  vs Aslan Karatsev [Q]
Fresh from a surprise upset over third seed Dominic Thiem and yet to drop a set this fortnight, Dimitrov has a chance to reach his fourth ever major semifinal. But standing in his way is an unheralded Russian, who is vying to become the first man to reach the final four on his Grand Slam debut. The No. 114 in the world is already the lowest-ranked player in three decades to reach the quarterfinals in Melbourne. Dimitrov has experience on side, with nine of ten clashes with qualifiers at majors going his way. But getting past the in-form Karatsev will be a challenge – the hard-hitting 27 year-old plays an explosive brand of tennis and dismantled both eighth seed Diego Schwartzman and 19th seed Felix Auger-Aliassime to earn his quarterfinal berth. Dimitrov plans to block out his opponent’s success and simply hone in on what he can control. His plan? “Just focus on your side of the net, focus on your game plan, control what you can on your end and then progress through.”