2021 Citi Open

Between 2011 and 2019, the Citi Open hosted conjoining men and women tournaments. However, amid the COVID-19 pandemic in 2020, the Women's Tennis Association (WTA) revoked its sanction of the Citi Open for the year's tour and added two events to its provisional calendar instead: the Top Seed Open in Lexington, Kentucky and the Prague Open.^[4] After the Citi Open returned in 2021 from the event's eventual cancellation in the prior year,^[5] the WTA stayed its revocation of the event's sanction, so the women's tournament did not return as many women's players had scheduling conflicts with the 2020 Summer Olympics.^[6] In its place, event officials created the inaugural women's invitational as a three-day exhibition during the US Open Series. Coco Gauff, Jessica Pegula, and Jennifer Brady were the three original headliners,^[7][8] though Brady was later replaced by Victoria Azarenka.^[9]

The players played in a round-robin format; the winner of each pair in their first matches would then play each other in the final match.^[9][10] The games were played in a best-of-three set format with regular scoring and a 10-point "super tiebreak" to decide the third set. The player with the best record would be crowned the champion and in the case of a tie, the winner would be decided by the player who won the most sets or games. Because the tournament was not sanctioned by the WTA, the players would not accrue or lose any points. The prize money for the inaugural champion was set at $25,000.^[11] On August 5, Gauff defeated Azarenka in the first match, 6–3, 6–1.^[9][10] Azarenka was scheduled to play Pegula the following day, after Brady withdrew from the tournament, to decide the final match, but Azarenka herself later withdrew from the invitational after suffering an ankle injury.^[12] On August 7, Pegula defeated Gauff in the final match, 4–6, 7–5, [10-8], to win the invitational.^[13]