Coco Gauff, 15, stops Naomi Osaka at the Australian Open and becomes the youngest player since 1991 to beat a top-5 opponent. (2:01)

Friday's slate at the Australian Open was all sorts of funky. On the women's side, seven-time champ Serena Williams lost against Qiang Wang, No. 3 seed and defending champion Naomi Osaka got pushed around by 15-year-old Coco Gauff and No. 10 Madison Keys got swept out by Maria Sakkari.

On the men's side, No. 6 Stefanos Tsitsipas lost in straight sets versus Milos Raonic, and No. 9 Roberto Bautista Agut lost in five to Marin Cilic. Even Roger Federer flirted with disaster, being pushed to a fifth-set 10-point-rule tiebreaker by Aussie John Millman (trailing 8-4 at one point), but the universe evidently decided that was too much for one day, as Federer won the final six points to pull out the third-round victory.

With about half of the round of 16 field filled in, only two top-10 seeds remain in the bottom half of the men's draw and top half of the women's side. The betting favorites remain the same on the men's side, but, without Williams and Osaka, the women's draw has been tipped on its head.

In this moment of regrouping before the second half of Round 3, however, we're gripped with another question: can Serena still win another slam?

This is where it's good to have numbers to consult.

Williams has still been excellent since her return from having a child -- she had, after all, made four of the past six Grand Slam finals before Melbourne and, in New Zealand earlier this month, won her first WTA title in three years. But while Colin Davy's rankings placed her at No. 2 overall and No. 1 on hard courts, her percentile ratings above (88.2 overall, 93.5 on hard) pretty clearly hint at the vulnerability we've seen from her in those four slam finals, all straight-set losses. She is still brilliant, but her dominance is indeed less than it has been, which makes her more susceptible to upsets against players like Qiang (37th overall, 30th on hard courts).

Women's top 25 Player Overall % Rank Hard court Rank Clay Rank Grass Rank Ashleigh Barty 88.4 1 90.5 3 87.0 2 86.1 2 Serena Williams 88.2 2 93.5 1 84.6 4 86.6 1 Naomi Osaka 85.8 3 91.9 2 82.1 5 77.6 4 Simona Halep 85.3 4 85.7 6 88.1 1 83.3 3 Elina Svitolina 81.9 5 85.7 6 80.4 6 72.3 13 Karolina Pliskova 81.2 6 84.3 8 79.4 7 77.3 5 Bianca Andreescu 80.5 7 87.8 5 75.4 12 74.6 7 Kiki Bertens 79.2 8 76.3 17 86.6 3 73.3 9 Petra Kvitova 78.4 9 79.3 12 77.9 8 75.8 6 Aryna Sabalenka 77.9 10 88.2 4 67.9 27 69.3 16 Belinda Bencic 76.7 11 80.6 10 72.9 15 73.7 8 Karolina Muchova 76.2 12 76.7 16 77.4 10 72.7 11 Sofia Kenin 75.8 13 83.4 9 71.1 18 68.7 19 Madison Keys 75.6 14 79.4 11 73.8 13 72.0 14 Johanna Konta 73.9 15 77.7 14 69.4 24 73.3 9 Victoria Azarenka 73.3 16 78.9 13 68.5 25 66.7 22 Elise Mertens 73.0 17 77.0 15 71.8 16 69.5 15 Dayana Yastremska 73.0 18 74.4 18 73.8 13 68.8 18 Marketa Vondrousova 72.8 19 70.8 24 77.2 11 65.4 25 Petra Martic 72.8 20 73.2 19 77.7 9 67.0 21 Donna Vekic 71.0 21 72.6 20 70.8 20 69.2 17 Caroline Wozniacki 68.8 22 72.6 20 63.1 33 66.0 24 Amanda Anisimova 68.5 23 67.9 26 71.1 18 66.5 23 Maria Sakkari 67.9 24 70.9 23 71.2 17 60.8 27 Rebecca Peterson 65.6 25 71.2 22 63.7 32 57.1 34

Williams' rating isn't the only one that has slipped, by the way. While the men's Big Three (Rafael Nadal, Novak Djokovic and Federer) are the only players on either tour with an overall percentile rating in the 90s, Djokovic's hard-court rating was in the 99th percentile in mid-2016, and Federer's was in the 98th just two years ago. Heading into the Australian Open, they were at 97.5 and 96.4, respectively -- still tremendous, but slightly more vulnerable. Djokovic dropped a set against veteran Jan-Lennard Struff in the first round before Federer got taken to the brink by Millman.

Men's top 25 Player Overall % Rank Hard court Rank Clay Rank Grass Rank Rafael Nadal 96.6 1 97.3 2 99.5 1 91.0 3 Novak Djokovic 96.3 2 97.5 1 97.1 2 92.2 2 Roger Federer 94.7 3 96.4 3 93.1 5 92.4 1 Stefanos Tsitsipas 89.7 4 90.8 5 93.2 4 77.8 5 Daniil Medvedev 89.0 5 93.9 4 84.6 15 84.0 4 Juan Martin del Potro 86.2 6 88.8 6 87.6 10 75.0 7 Dominic Thiem 85.8 7 82.9 16 96.7 3 73.5 9 Alexander Zverev 85.4 8 84.6 13 92.3 6 74.7 8 Stan Wawrinka 83.0 9 85.8 8 90.3 7 63.0 35 Andrey Rublev 82.2 10 84.9 12 82.2 20 70.5 19 Roberto Bautista Agut 81.5 11 85.8 8 79.6 27 77.0 6 Kei Nishikori 81.1 12 81.0 22 85.8 14 71.8 15 Gael Monfils 80.7 13 83.5 14 81.8 23 68.3 22 Karen Khachanov 80.6 14 82.9 16 82.0 21 72.9 11 David Goffin 80.0 15 80.8 23 83.7 16 72.3 12 Alex De Minaur 79.2 16 88.4 7 69.7 58 72.1 13 Pablo Carreno-Busta 79.1 17 82.5 18 86.3 12 63.9 31 Denis Shapovalov 78.9 18 85.1 11 73.7 46 68.8 20 Matteo Berrettini 78.8 19 81.7 20 81.2 24 73.4 10 Grigor Dimitrov 78.8 20 82.3 19 76.7 36 66.0 27 Nick Kyrgios 78.1 21 85.2 10 74.1 45 71.2 17 Jo-Wilfried Tsonga 77.9 22 79.9 24 76.1 37 71.9 14 Diego Schwartzman 76.9 23 72.9 37 89.1 9 68.5 21 Kevin Anderson 76.8 24 83.1 15 74.7 43 66.7 25 Filip Krajinovic 75.6 25 70.0 43 89.4 8 63.5 34

Projecting the rest of the Australian Open

With the dust settling after a wild day Down Under, we can use Davy's numbers to reestablish our bearings and figure out title odds moving forward. The men's favorites haven't changed to any major degree -- Djokovic began the tournament with a 42% chance, Nadal 21%, Federer 20%, and Daniil Medvedev 6%; that hierarchy remains intact. Things have changed dramatically on the women's side, however:

Odds of winning the women's tournament:

•Barty-* 28%

•Pliskova 15%

•Halep 11%

•Kenin-* 10%

•Kvitova-* 9%

•Svitolina 6%

•Mertens 3%

•Qiang-* 3%

•Bencic 3%

•Bertens 3%

•Sakkari-* 2%

•Vekic 2%

*-Players with asterisks have advanced to the fourth round.

When the tournament began, Williams had a 30% chance, and Osaka was at 8%. With those players out, Barty's odds (9% at the beginning of the tournament) have increased considerably, as have those of players like Pliskova (started at 10%), Halep (7%), Kenin (3%), and Kvitova (4%).

Projecting the next two years' worth of slams

Fred Lee/Getty Images

Since we're constantly wondering about when the sport's all-timers are going to finally be overtaken by a younger generation, let's see what Davy's numbers have to say about the next two years' worth of slams.

Projecting slams, independent of the draws, requires some generalizations -- seeding approximations, generic draw difficulty. One's title odds can be absurdly draw-dependent, so the odds for each tournament will shift dramatically when the draw comes out. Still, Davy simulated each upcoming slam 2,000 times, each based on where ratings will approximately stand now and, using aging curves, in the future. It produced some interesting results:

Projected slam favorites over the next two years (ATP)

• 2020 French Open: Nadal 23%, Djokovic 17%

• 2020 Wimbledon: Djokovic 17%, Federer 17%

• 2020 US Open: Federer 19%, Djokovic 16%

• 2021 Australian Open: Djokovic 33%, Nadal 29%

• 2021 French Open: Nadal 22%, Djokovic 18%

• 2021 Wimbledon: Djokovic 20%, Federer 17%

• 2021 US Open: Djokovic 18%, Federer 18%

The specific percentages could change with a different sample size, but this lays out the favorites, and they're pretty familiar.

Average projected slam titles over the next two years (ATP)

By simply adding the percentages together (a 23% chance = 0.23 titles), we can come up with a loose average of how many slams each player is projected to win.

• Djokovic 1.8 (best odds: 2020 Aussie 42%)

• Nadal 1.1 (best odds: 2021 Aussie 29%)

• Federer 1.1 (best odds: 2020 Aussie 20%)

• Medvedev 0.4 (best odds: 2020 US Open 9%)

• Stefanos Tsitsipas 0.4 (best odds: 2020 US Open 8%)

• Zverev 0.3 (best odds: 2020 French Open 7%)

• Alex De Minaur 0.2 (best odds: 2021 US Open 6%)

There are two ways to look at this.

1. The new overlords are the old overlords. Even with aging curves baked into the numbers, Djokovic, Nadal, and Federer are in most cases the top three favorites (or three of the top four) for any given slam.

2. On average, the Big Three are still projected to win only four of the next eight slams. Part of this is because these projections are, by nature, conservative. But these totals also serve as a reminder that the Big Three's collective form is indeed down from career peaks. And as Djokovic, Nadal and Federer continue to age, they might be more dependent on strong draws and easy first-week runs than they used to be. The door could be open for rising stars to begin stealing some upsets.

Darrian Traynor/Getty Images

Projected slam favorites over the next two years (WTA)

• 2020 French Open: Halep 13%, Barty 10%

• 2020 Wimbledon: Williams 13%, Barty 12%

• 2020 US Open: Williams 19%, Osaka 12%

• 2021 Australian Open: Williams 16%, Osaka 13%

• 2021 French Open: Halep 11%, Barty 9%

• 2021 Wimbledon: Williams 14%, Barty 11%

• 2021 US Open: Williams 20%, Osaka 11%

Average projected slam titles over the next two years (WTA)

• Barty 1.0 (best odds: 2020 Aussie 28%)

• Serena Williams 1.0 (best odds: 2021 US Open 20%)

• Halep 0.7 (best odds: 2020 French Open 13%)

• Osaka 0.6 (best odds: 2021 Aussie 13%)

• Pliskova 0.6 (best odds: 2020 Aussie 15%)

• Sabalenka 0.4 (best odds: 2021 US Open 9%)

• Svitolina 0.4 (best odds: 2020 Aussie 6%)

• Kvitova 0.3 (best odds: 2020 Aussie 9%)

• Kenin 0.3 (best odds: 2020 Aussie 10%)

• Kiki Bertens 0.3 (best odds: 2020 French Open 9%)

• Bianca Andreescu 0.3 (best odds: 2021 Aussie 6%)

The typical WTA slam is a Thunderdome of players with similar talent levels, attempting to win seven consecutive best-of-three matches. That Serena has won 23 of these is mind-blowing, and these numbers back up just how difficult projecting a tournament winner can be. They give her a 65% chance of winning one of these next seven and a 25% chance of winning more than one. That means there's a 35% chance she wins none. Those odds are probably higher than they would have been a year ago.

And what about Coco Gauff?

These numbers are based on long-term trends, aging curves, etc., and there aren't many recent examples of what Gauff has recently accomplished. The 15-year old plays limited events because of WTA Tour age rules, but has won eight matches at the past three slams -- and just avenged her third-round 2019 U.S. Open loss by topping Osaka on Friday in Melbourne.

Again, Davy's ratings are designed not to overreact to small samples. The simple fact Gauff headed into this tournament already ranked 79th in his ratings is impressive, but at that level, she is not going to be given good odds of making major noise in the second week of a slam. In fact, she is given just a 17% chance of advancing past Kenin in the fourth round. If Gauff were to continue one-upping herself in slam performances, perhaps reaching a quarterfinal or semifinal, then going even further, it would be pretty definitive proof of her once-in-a-generation potential. The stats don't see that happening right now, but they are not really designed to see the unicorns.