Wednesday's Guadalajara round of 16 pits Janice Tjen against Sloane Stephens on hard. Janice Tjen comes in at 4 wins from the last ten. Sloane Stephens comes in at 4 wins from the last ten.

The serve is where this match separates: Tjen has been winning 67.5% of first-serve points to Stephens's 60.8%, and on hard that gap compounds fast. This one is close to a coin flip, and the lean toward Tjen is exactly that — a lean.