Stephens is 4-4 in her last eight matches, having reached the second round in Montreal the highlight of her summer. She's played four consecutive three-set matches.
Meeting for the seventh time, Stephens leads the head-to-head against Keys 4-2. This is their first match on hardcourt since they contested the championship match four years ago.
This will be a contrast in styles as Stephens will play an all-court, defensive game and be aggressive when she feels she needs to be. Keys will want to dominate with her serve and groundstrokes, playing shorter rallies from the baseline.
Longer rallies will favor Stephens as she will likely be able to extract errors from Keys. Both players will look to serve well to set up the style they want to play. Stephens has the edge in movement as she is one of the most athletic players on tour.
It's a long way from when they squared off for the championship in 2017 as they've gone from that to one of them being out of the tournament after just a couple of hours. both players are far from their best, but it'll be good to see one of them get a much-needed victory.
Whenever they play, it seems Stephens is able to implement her style of play and force Keys into enough errors to come out on top, but what will give the 2017 runner-up confidence is besting Stephens on the clay of Charleston.
Expect an up-and-down affair with many twists and turns, but Stephens to win a close match.
Prediction: Sloane Stephens in three sets