The two best players since the season restart will collide on Saturday, as No.9 Naomi Osaka and No.27 Victoria Azarenka face-off for the US Open title. The match-up pits Azarenka's 11-match win-streak against Osaka's 10-match win-streak in a rematch of the Western & Southern Open final that never was, with both former No.1s vying for their third major titles.

Here are five things to look out for when the tour's two hottest players lock horns on Arthur Ashe Stadium. 

READ: US Open Final Countdown

Osaka's Serve vs. Azarenka's Return: Who wins the battle?

Osaka has been broken just five times over the tournament, winning 93% of her service games across six matches. When she has needed her serve on big points, it has come through for her. Osaka has saved 76% of the breakpoints she has faced, compared to Azarenka's 50%.

Service Stats: Osaka vs. Azarenka
Aces: 35 vs. 16
Double-faults: 10 vs. 17
Unreturned 1st Serves: 44% vs. 27%
1st Serves Won: 81% vs. 68%
2nd Serves Won: 57% vs. 48%
Break Points Saved: 76% (16 of 21) vs. 50% (13 of 26)
Service Games Won: 93% (65 of 70) vs. 78% (47 of 60)
Number of Times Broken: 5 vs. 13

But Osaka has not faced a returner of Azarenka's quality in the tournament, and the pressure the two-time Australian Open champion builds not just on the return of serve but through the subsequently neutralized rallies is unparalleled when she is at her best. And while Osaka has not faced a returner of Azarenka's level, Azarenka comes into Saturday's final having fended off the biggest serve in the game.

"There are some players who are able to generate power with their arms. I'm able to generate a lot of power and redirecting the ball with my movement."

- Victoria Azarenka

En route to her first win over Serena Williams at a major, Azarenka broke the American three times and suffocated her second serve. Azarenka has won over half her return games all tournament and her success rate when returning second serves has been off the charts. Azarenka has won 69% of her returns against second serves and she won 63% against Serena in the semifinals. Osaka's second serve has improved but remains attackable, and if her first serve percentage drops, Azarenka will be ready to pounce.

Return Stats: Azarenka vs. Osaka
Return Points Won vs. 1st Serve: 43% vs. 36%
Return Points Won vs. 2nd Serve: 69% vs. 53%
Return Winners: 11 vs. 6
Break Points Won: 49% vs. 36%
Return Games Won: 55% vs. 30%

Getty Images

Who will find the balance between aggression and consistency?

Saturday's final will feature two aggressive players who impose themselves in two different ways. For Osaka, it's about pace of shot. For Azarenka, it's about taking the ball early from the baseline and rushing her opponent into either forced errors or giving up short balls that she can put away.

"There are some players who are able to generate power with their arms," Azarenka said. "I'm able to generate a lot of power and redirecting the ball with my movement."

"The timing is really important, to be able to cut those angles, to be able to rush your opponent with maybe not as much power, but with that precision and closer to the ball."

With both women looking to control the rallies, the question is who can do so while minimizing their unforced errors. Both Osaka and Azarenka have cleaned up their games in the second week of the tournament. In her last five sets against Jennifer Brady (SF) and Shelby Rogers (QF), Osaka has hit a total of 25 unforced errors, an average of five per set. Azarenka is not far behind, hitting 28 in her last five sets.

Wim Fissette has worked with Osaka during the shutdown to clean up her game, crediting her work with new trainer Yutaka Nakamura and some minor technical corrections for her cleaner game.

"My plan to clean up the unforced errors is first footwork," Fisette said. "Everything starts with the footwork. She has been working really hard. We had about 10 weeks in L.A. I was very happy with that.

"We have Yutaka onboard, great experience as a fitness coach, did a really good job with her. Combination of just, like, improving the footwork, always have like the steady and the strong position behind the ball. That's the base.

"Second, of course, it's also technically little corrections, things that she can focus on even during the match, like more spin, more racquet head speed, so actually more acceleration is often more control. Just to remind her a little of, like, technical things that also helps.

"On the other hand, she always has been like this player who wants to build the point. I feel like her unforced errors in the past were not really, like, making bad choices, especially not the last two years, but it was more maybe the footwork was a bit sloppy, and technically she could have done a few things better. I think this is also for us to move forward in the future."

"I feel it's a very close match with the two players who have been playing the best tennis the past three weeks."

- Wim Fissette

Will Wim Fissette prove the difference?

Before coaching Osaka, Fissette coached Azarenka with great success. Azarenka hired the veteran Belgian coach in 2015 and would go on a tear in 2016, winning the Sunshine Double, before stepping away from the tour due to pregnancy. Fissette stuck with Azarenka for her comeback before splitting last year and being hired by Osaka last December.

"I guess it's for sure an advantage," Fissette said. "It's always good to know the opponent really well. On the other hand, preparing matches, I always try to get in the head of the opponent and try to understand the opponent exactly based on videos and based on statistics, of course.

"Of course, I know Vika's game pretty well. But I do feel like it's finals of the US Open. It's all about controlling the emotions and trying to play the best tennis at the right moment.

"A few key points are going to make the [difference] tomorrow. That's how I feel. Maybe an ace at the right moment or a double-fault at the wrong moment can decide this match.

"I feel it's a very close match with the two players who have been playing the best tennis the past three weeks. I'm sure it's going to be a huge battle out there tomorrow."

Getty Images

Who will make the quick adjustments?

Osaka and Azarenka find themselves in the final battle-tested. Osaka has lost three sets en route to her third major final, and she has had to dig deep in particular to get past Marta Kostyuk in the third round, 6-3, 6-7(4), 6-2, and edging Jennifer Brady 7-6(1), 3-6, 6-3 in Thursday's high-quality semifinal.

"She's a player which I saw before I was working with her, she understands the game well," Fissette said. "I've seen her adjust tactics by herself during the matches. I think that's a huge quality.

"I also saw that yesterday during the match. For example, she changed her return position to go a little bit more back after the second set. She is adjusting really well. She's thinking and she's adjusting. It's a great combination."

Azarenka has dropped just two sets, but she was forced to quickly problem-solve against unfamiliar opponents in Iga Swiatek and Karolina Muchova, and overcame a sluggish start against Serena to make the necessary to corrections to ultimately dominate the second and third sets.

"In the beginning, it was a lot of very short rallies," Azarenka said after her semifinal win. "She served really, really well. I felt like I was kind of out of range. I wasn't finding my serve. Second serve was getting killed.

"I knew I had to get into the rallies, I needed to step up with my aggressivity, play a little smarter, play with a little bit more width of the court and bring the intensity up. I felt that intensity was important today, to bring it up."

This will be the first match on hardcourt between Osaka and Azarenka since the 2016 Australian Open. Both women were in very different places in their careers at the time. Azarenka had just dominated the field at the Brisbane International, blitzing Osaka in the Australian Open third round 6-1, 6-1. Osaka was still ranked outside the Top 100 and was two years away from winning her first WTA title.

"Honestly, I feel like the older you get, the more mentally strong you are."

- Naomi Osaka

Who will handle the occasion better?

Osaka brings a 2-0 record into her third major final, having won the 2018 US Open (d. S.Williams) and 2019 Australian Open (d. Kvitova). Azarenka is contesting her fifth major final and first in seven years (2013 US Open). The Belarusian is 2-2 in Slam finals and 0-2 at the US Open (2012, l. S.Williams; 2013, l. S.Williams). Osaka, 22, is bidding to become the youngest three-time major winner since Maria Sharapova in 2008 and the first Asian player, man or woman, to hold three major titles. Should 31-year-old Azarenka prevail, she would become the second-oldest player to win her third Slam title behind only Virginia Wade. 

Azarenka has handled her winning-streak perfectly so far, never getting ahead of herself or allowing her ambition to turn into expectations. She has been incredibly relaxed over the last three weeks and has kept her winning ways in perspective, a remarkable feat given she ended a 12-month losing-streak only three weeks ago. 

"It's a final tomorrow, but I will say to her that, Vika, it's a match," Azarenka's coach Dorian Descloix said. "It's a tennis match. We don't know if it's finals, first round, second round, Vika. It's just a match. We don't change.

"We keep exactly the same routine, same thing. We are gonna talk before the match. We are gonna laugh, we're gonna talk and just relax. And just, Vika, go on the court and enjoy, enjoy the moment, enjoy this final. You deserve to be in the final today, so just enjoy it."

Osaka's mantra since resuming her season at the Western & Southern Open has been about maintaining a positive attitude. She has been able to play her top-level tennis over the last three weeks while continuing her activism against racial injustice and police brutality. In the face of the swirl around her, Osaka has cut a calm, confident, and quiet figure who is simply going about her business. Of her Slam campaigns, the 2020 US Open has been her most workman-like, a purposeful procession towards a title that many favored her to win before the draw. 

"Honestly, I feel like the older you get, the more mentally strong you are," Osaka said. "I think that's something that you learn from being on the tour for such a long time, playing so many matches.

"But for me, definitely my goal during these two tournaments was to be more mentally strong and to, like, fight for every point. So that's what I'm going to go into the final with. Nothing is going to change that."

US Open Final Preview: Naomi Osaka vs. Victoria Azarenka