Just how dominant has Jannik Sinner been on hard courts?
The ginger-haired Italian went 53-3 on the surface last year, his lone defeats coming against Carlos Alcaraz twice and Andrey Rublev.
Since the middle of the Shanghai Masters in October, only one man – the spirited Australian wildcard Tristan Schoolkate, this week – has grabbed a set off Sinner.
Like women’s No. 1 Aryna Sabalenka, he is the reigning Australian Open and US Open champ.
But if their head-to-head record is anything to go by, Sinner’s fourth-round match on Monday against Holger Rune at Australian Open 2025 could be a day session blockbuster.
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They have split their four matches – including both on hard courts – with all four going the distance.
Yes, their last hard court contest came in 2023 at the ATP Finals, before Sinner truly took off.
Rune, though, has a knack for testing the cream of the crop. Besides Sinner, the Dane sporting the backward cap routinely pushes Novak Djokovic and Alcaraz.
All of which Sinner, the ice to Rune’s fire, knows himself.
“We always had tough matches in the past,” Sinner said. “Let's see what's coming.
“For sure he's someone who can raise the level very, very high. Knowing that, I also have to raise my level.”
Sinner felt he raised his level in the third round against Marcos Giron on Saturday, when he varied his game – adding to his fierce slugging from the baseline.
“I tried to make some serve and volleys, some dropshots, trying to have a good feel with the court,” said Sinner.
That comes more naturally to Rune, whose ranking has dipped to No. 13 from a high of No. 4 during the time that Sinner’s has rocketed.
There have been injuries, coaching changes and questions surrounding his tactics.
His famed grit, however, has been on show through three rounds at Melbourne Park, outlasting Zheng Zhizhen in five sets, Matteo Berrettini in a long four and then Miomir Kecmanovic in another five.
Rune overturned major deficits against Berrettini – the former Wimbledon finalist – in two of the sets he won and trailed Kecmanovic by two sets to one and 4-2 in the fourth.
Seemingly hampered by a leg cramp – not new for the 21-year-old – he started to hit even bigger from the baseline, making a remarkably high percentage of those go-for-broke strikes to reverse the deficit.
Given the quality – the pair combined to produce 128 winners and only 81 unforced errors – it figures to go down as one of the matches of 2025.
Just how Rune pulls up physically against Sinner is an obvious consideration with 14 sets already under his belt.
While Sinner and Rune were, based on the seedings, expected to meet in the fourth round at Melbourne Park, very few could have predicted a final-16 clash between Iga Swiatek and Eva Lys.
Swiatek’s inclusion in the second week is no surprise, but Lys’s is. The German ranked 128 – a magic number in tennis, the draw size at Grand Slams – lost in the final round of qualifying.
A very late call came to take 2024 quarterfinalist Anna Kalinskaya’s spot and in her first Grand Slam main draw in five years, the lucky loser took her chance.
MORE: AO 2025 women's singles draw
The 23-year-old was more than happy to again change the departure date of her flight, which was meant to be Sunday once she entered the main draw.
“It definitely doesn't feel real for me right now,” said Lys, whose Ukrainian father played pro tennis. “I don't know when the realisation will kick in.
“It's definitely an insane story, how it happened, how fast it happened. Those days have totally changed my life.”
Lys and Swiatek faced off once before, on the Pole’s favoured surface of clay in Stuttgart three years ago. A qualifier back then, Lys fell 6-1 6-1.
“I do think that you always have a chance going out,” said Lys. “You never know what's going to happen in the match. I will just try to keep my streak going, try to keep my spirit going. I'm just going to go out and enjoy.”
Swiatek, seeking a first Australian Open quarterfinal in three years, has only dropped 10 games in three matches.
The five-time Grand Slam winner feels better than 12 months ago, when she said a tough draw and physical issues contributed to a fourth-round exit.
“Now I feel much more fresh,” said Swiatek. “I feel like everything is in the right spot and working. I can just focus on the game, and that's it.
“Yeah, I feel less stress. It's helping, for sure.”
Elsewhere on Day 9, home hope Alex de Minaur follows in the night session at Rod Laver Arena against Next Gen American Alex Michelsen.
Gael Monfils, 38, and fellow showman Ben Shelton, meanwhile, battle for the first time at Margaret Court Arena in the evening.
By then, Monfils’ wife, Elina Svitolina, should have completed her match against Veronika Kudermetova kicking off proceedings at Rod Laver Arena.