Back, Ku, Park complete Korean sweep, tie 42-year record in Seoul
Three South Korean players have made the second round of a WTA tournament for the first time in 42 years at this week's Korea Open in Seoul.
On Monday, 24-year-old Back Dayeon upset Yuan Yue 6-3, 4-6, 6-1 to reach the second round of the event for a second time. On Tuesday, fellow wild cards Park Sohyun and Ku Yeonwoo completed a 100% first-round sweep for home players, with both claiming the first tour-level victories of their careers. Park, 24, upset 's-Hertogenbosch champion Robin Montgomery 7-6(4), 6-3, then Ku, 23, cruised past Alevtina Ibragimova 6-3, 6-2.
How many times have three South Koreans won matches at a WTA event?
The only previous time in the Open Era that three South Koreans have made the second round of a WTA event was at Rio de Janeiro 1984, when Han Eun-Sook was a quarterfinalist and Helen Park and Lee Jeong-Soon fell in the second round. All three were qualifiers.
The Korea Open has been on the WTA calendar since 2004. Two Koreans have made the second round in two of its tour-level editions -- in 2013 (Jang Su-Jeong and Lee Ye-Ra) and 2023 (Jang and Back). Jang, who defeated Klara Koukalova and Ons Jabeur to make the last eight in 2013, remains the most recent South Korean player to reach a WTA quarterfinal.
Who are Back, Park and Ku?
This week's trio of South Korean winners are all former Top 50 juniors with several years of wild card experience in Seoul under their belts.
Ku is the youngest and most accomplished of the three to date. She came through qualifying at Seoul 2023 to make her tour-level debut while ranked No. 540, but her significant career surge came last year. Ku cut her ranking from No. 523 last April to crack the Top 200 by November courtesy of a remarkable 63-22 season record; she ended 2025 by winning 18 of her final 20 matches, collecting consecutive W35 titles in Portugal, then making back-to-back finals at the Takasaki W100 and Yokohama W50. In 2026, Ku has made her qualifying debut at each of the Grand Slams -- at Roland Garros, she whitewashed former World No. 1 Karolina Pliskova in the first set before falling 0-6, 6-3, 6-1, and she made the second qualifying round at the US Open. She hit her career high of No. 171 in July, and is presently No. 185.
Back made her tour-level debut as a wild card at Seoul 2022, and the following year pulled off her career-best victory by stunning top seed Jelena Ostapenko 3-6, 6-1, 7-6(4) in the first round. Back was ranked No. 569 at the time; Ostapenko was No. 13, and just over a month previously had herself upset World No. 1 Iga Swiatek in the US Open fourth round. Back has continued to make steady progress since. She compiled a 17-match winning streak in May and June this year, encompassing three W35 titles in Andong, Changwon and Taipei and pushing her ranking to a career high of No. 245 in July. Back is currently No. 272.
Park made her tour-level debut as an unranked 18-year-old wild card at Seoul 2018, and in 2022 stretched former No. 10 Kristina Mladenovic to three sets in a 6-4, 4-6, 6-3 first-round loss. She is a 10-time World Tennis titlist, including the Goyang W35 this April. Park set her career high ranking of No. 244 this February, and is currently at No. 329.
What's next for the home trio?
In the second round, Park will face No. 3 seed Lanlana Tararudee, Back will take on No. 5 seed Maya Joint and Ku is pitted against No. 4 seed Elena-Gabriela Ruse. Park and Ku will both be bidding for their first completed Top 100 win (Park previously defeated Wang Xiyu via retirement in 2024 Billie Jean King Cup action).
Should two or more of the trio pull off a second-round upset, it will mark the first time in the Open Era that multiple South Korean players have reached the last eight of a WTA tournament.
Only two South Korean players have reached tour-level quarterfinals this century -- Jang and former No. 45 Cho Yoon-Jeong, a three-time WTA finalist (Pattaya 2002, Auckland 2003, Canberra 2006).
