Wednesday's US Open round of 64 pits Marta Kostyuk against Sloane Stephens on hard. Marta Kostyuk is 7-3 across recent matches. Sloane Stephens has won 4 of the last 10.

Marta Kostyuk is clearly higher-rated on hard — our number puts Kostyuk around 81%. Stephens needs several things to break right at once; the percentages say they usually don't.