Key stats, notable quotes and what you need to know about the 2021 Australian Open quarterfinalists

Photos: Meet the remaining players Down Under | W2W4: Quarterfinal preview 

The matches have come and gone, 120 to be exact, leading to the 2021 Australian Open quarterfinals. Let's take stock of each player's run to the elite eight:

[22] Jennifer Brady (USA) vs. Jessica Pegula (USA)
Head-to-head: Pegula leads 1-0, which came at the Western & Southern Open last year -- the event directly before Brady's run to the 2020 US Open semifinals at the same site.

Brady: Serving notice again

The path: It has been smooth sailing for Brady, who has not dropped a set in four matches. A win over No.28 seed Donna Vekic in the fourth round put her into her second Grand Slam quarterfinal.

The numbers: Brady advanced to the 2020 US Open semifinals without dropping a set, then pushed eventual champion Naomi Osaka to three sets in their encounter, meaning she is 19-2 in sets over the past two hardcourt Grand Slam events. Brady's serve has only been broken twice during this fortnight, and she did not even face a break point in her first two matches.

The words: "During my matches, I’m not drifting in and out with my focus," Brady said after her fourth-round win. "If I’m down 40-0 in a game, I’m still trying to win that game, so I’m trying to stay as present as possible by focusing on each and every point, I’m giving myself the best chance possible to make the match in straight sets. I’m gaining confidence with every match I play, and I don’t feel I have many weaknesses on the mental side right now."

Pegula: Racking up winners

The path: Pegula knocked off four current or former Top 10 players to earn a spot in her first-ever Grand Slam quarterfinal. A win over two-time Australian Open champion Victoria Azarenka in the first round portended a strong run. Pegula punctuated her trip to the elite eight with a three-set upset against No.5 seed Elina Svitolina.

The numbers: Pegula has hit more than 20 winners in each of her four matches, including 31 to beat Svitolina in the last round, for a total of 96. Pegula's victory over Svitolina was her first over a current member of the Top 10 in seven attempts.

The words: "I think I'm just playing really confident right now," Pegula said after her third-round win. "I'm obviously seeing the ball and hitting the ball really well. I'm just trying to not kind of let up really at all. I think also at the same time I'm doing a good job of staying in the point when I have to, not going for too much, but still going aggressive at the right times."

[3] Naomi Osaka (JPN) vs. Hsieh Su-wei (TPE)
Head-to-head: Osaka leads 4-1, but four of those five meetings have gone three sets, including a tough win during Osaka's 2019 Australian Open title run.

Osaka: Hardcourt major greatness

The path: Osaka, the 2019 Aussie Open winner, navigated through a tricky early draw with relative ease, beating dangerous floaters Anastasia Pavlyuchenkova and Caroline Garcia, and No.27 seed Ons Jabeur in straight sets. That momentum helped Osaka survive a close call against 2020 finalist Garbiñe Muguruza in the fourth round. Osaka saved two match points en route to a triumph, 7-5 in the final set.

The numbers: Another trophy would cement Osaka's status as the current top player at hardcourt Grand Slams. She previously reached the quarterfinals of a Grand Slam event three times, and she went on to win the title on each of those occasions (2018 US Open, 2019 Australian Open and 2020 US Open), giving her three of the past five hardcourt Grand Slam titles.

The words: "In a sense, whenever I play, I feel like the ball is on my racquet," Osaka said after her fourth-round win. "Whenever I play [Hsieh], there's a bit of hesitation in that mindset for me. So, yeah, it's definitely going to be tough. At the same time it's the quarters of a slam, so it would be weird if it wasn't tough."

Hsieh: Opportunity for more upsets

The path: Hsieh's reputation as a giant-killer in Grand Slams was bolstered by a swift victory over No.8 seed Bianca Andreescu in the second round, her fourth win over a Top 10 player at a major. Hsieh followed that up with a comeback win against Sara Errani before a milestone fourth-round victory over No.19 seed Marketa Vondrousova.

The numbers: Hsieh had been 0-3 in fourth-round matches at majors in her career, but she propelled herself into her maiden Grand Slam quarterfinal. According to her coach Paul McNamee, Hsieh viewed her match against Vondrousova as an "opportunity. She missed a couple of opportunities before. You don't know how many more you're going to get when you're at her age. She knew it was an important match."  

The words: "We all know she's a very good player," Hsieh said, looking forward to her clash with Osaka. "Anyone plays her, they will get troubles. I [will] not worry about it. She's probably going to smash me on the court. I try to play my game, do my job, see what happens."

[10] Serena Williams (USA) vs. [2] Simona Halep (ROU)
Head-to-head: Williams leads 9-2, but Halep won their last meeting in straight sets -- which happened to be the 2019 Wimbledon final.

Williams: Extended Aussie Open expertise

The path: Williams swept through the first three rounds without the loss of a set and lined up a heavily anticipated first meeting with Aryna Sabalenka in the round of 16. A hard-fought clash between the two Top 10 seeds went the distance, but Williams eventually prevailed 6-4 in the final set to earn a spot in her 13th Australian Open quarterfinal.

The numbers: Williams started her 20th campaign at the season-opening major with her 100th Australian Open match. Her staggering statistics grew as she kept winning, and she currently holds a 91-12 win-loss record at the Australian Open, having totaled more wins and matches at the event than any other woman in the tournament's history. Her seven Australian Open singles titles is also a record in the Open Era (since 1968).

The words: "I think it's great depth again," Williams said, as she reviewed the draw following her fourth-round win. "I think it's been a lot of players that really could win the title since the beginning of the draw. I think there's so many players that can come out and have won Grand Slams and can keep winning. It's good. It's good to see. It's good to see that I'm in that mix, too."

Halep: Mastering three-set turnarounds

The path: Halep got past two opponents who had troubled her in the past, but it wasn't easy. First, Halep defeated Ajla Tomljanovic in the second round, coming back from 2-5 down in the final set. Halep then faced Iga Swiatek in the fourth round, their first meeting since the teenager surprised her at 2020 Roland Garros. Halep got her revenge, charging back from a set down to make her fifth Australian Open quarterfinal.

The numbers: Halep has now improved to 9-3 in three-set matches at the Australian Open in her career. She had a trio of notable three-setters during her run to the 2018 final, beating Lauren Davis 15-13 in the final set in the third round and Angelique Kerber 9-7 in the decider in the semifinals before falling to Caroline Wozniacki in a grueling championship match.

The words: "She's the only one with 23 Grand Slams, so you cannot compare Serena with all of us, because we do not have so many Grand Slams," Halep said in advance of her quarterfinal. "But when I step on the court, it's just another opponent, and always I'm focused on myself more than I focus against who I play. And I'm trying to give my best to try everything I can to win that match."