How is Madison Keys not only in the top 20, but also just ahead of early breakout stars Eugenie Bouchard and Sloane Stephens, both of whom have deep Slam runs already in the books? Keys beats both of them by the slimmest of margins due to the new aging curves. Keys is the youngest of the three, and the aging curve gives a slightly bigger boost to younger players.
Advanced Baseline: Making the case for Madison Keys over Eugenie Bouchard
The new Advanced Baseline rankings are out -- view the men’s rankings here and the women’s rankings here -- and it had a bit of a surprise on the women’s side. Madison Keys, currently 42nd in the WTA rankings, is ahead of two other, more prominent younger players: Sloane Stephens (18th in WTA) and Eugenie Bouchard (19th).
Stephen Dunn
Still, why is AB even putting Keys in the same league as her contemporaries that have already achieved more? If you compare Madison’s and Eugenie’s results over the past 15 months, they’re a lot more similar than you might think.
Madison Keys
| Record vs. | W-L | Average GDR* in wins | Average GDR* in losses | Differential |
| Advanced Baseline Top 25 | 4-12 | 0.42 | 0.28 | +0.14 |
| No. 26-50 | 7-6 | 0.24 | 0.32 | -0.08 |
| No. 51-100 | 10-5 | 0.38 | 0.18 | +0.20 |
| No. 100+ | 22-5 | 0.41 | 0.09 | +0.31 |
Eugenie Bouchard
| Record vs. | W-L | Average GDR* in wins | Average GDR* in losses | Differential |
| Advanced Baseline Top 25 | 6-16 | 0.22 | 0.26 | -0.04 |
| No. 26-50 | 3-6 | 0.39 | 0.29 | +0.10 |
| No. 51-100 | 16-4 | 0.33 | 0.16 | +0.16 |
| No. 100+ | 32-7 | 0.37 | 0.08 | +0.28 |
* GDR stands for Game Differential Ratio, the games a player wins minus games a player loses, all divided by total number of games played. The idea behind GDR is that it encapsulates the scoring margin by incorporating game differential, but also accounts for if a match goes 2 sets vs. 3 by weakening the margin if more games are played in a 3-set match. Winning GDRs can range from -0.2 (representing a 7-6, 0-6, 7-6 win) to 1.0 (representing a 6-0, 6-0 win).
Their splits are nearly identical. Keys is actually maintaining a positive GDR differential against top-25 competition despite a losing record, so her top wins are actually a little more impressive. The reason Bouchard’s WTA ranking is higher is because she’s actually taken advantage of her opportunities.
Keys and Bouchard were in the same soft section of the Australian Open draw this year, but Bouchard was the one that lived up to the moment, playing her way to the quarterfinals without facing a ranked opponent. Keys, meanwhile, suffered a tough, three-set loss to Jie Zheng. (Tough three-set losses have been common this year. She fell to Shuai Zhang, 6-4 in the third, in Acapulco, and she fell, 7-6 in the third, to Shuai Peng in Charleston. That’s a good way to both maintain a solid AB ranking while allowing your WTA ranking to sag.)
Keys will probably stay below Bouchard during the next few months of clay season, thanks to clay being Keys’ worst surface. But I wouldn’t put it past her to have a deep run at Wimbledon this year.
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