Su Wei Hsieh defeated Kim Clijsters 6–3, 5–7, 6–3 in the first round of the WTA 250 Chicago tournament on hard court on 27 September 2021, confirming her status as pre-match favourite despite Clijsters' odds of 2.4 to Hsieh's 1.63. The result saw Hsieh recover from losing the second set to secure victory in three, advancing to the next round whilst Clijsters' comeback campaign continued to face obstacles against established tour players.