Champion in Båstad 2019 – Singles and doubles.
SINGLES
Winner (1): 2015 – Luxembourg.
Finalist (2): 2019 – Hiroshima; 2016 – Kaohsiung.
DOUBLES
Winner (2): 2019 – Hiroshima (w/Hibino), 2014 – Istanbul (w/Svitolina).
Finalist (1): 2015 – Tokyo [Japan Open] (w/Nara).
ADDITIONAL
WTA 125K Series Titles – Singles (2): 2019 – Bastad; 2016 – San Antonio.
Japanese Fed Cup Team, 2011, 2013-15, 2017, 2019-20; Japanese Olympic Team, 2016.
| Date | Rd | Match | Score | Time |
| 2019 | F | Doi d. Danka Kovinic [MNE] | 6-4 6-4 | 01:20 |
| 2019 | SF | Doi d. (8)Aleksandra Krunic [SRB] | 6-1 7-5 | 01:22 |
| 2019 | QF | Doi d. (4)Mona Barthel [GER] | 6-2 3-6 6-2 | 01:49 |
| 2019 | R16 | Doi d. (7)Elena Rybakina [KAZ] | 4-6 6-4 6-4 | 02:00 |
| 2019 | R32 | Doi d. Alison Bai [AUS] | 6-1 6-1 | 01:00 |
Champion in Båstad 2019 – Singles and doubles.
SINGLES
Winner (1): 2015 – Luxembourg.
Finalist (2): 2019 – Hiroshima; 2016 – Kaohsiung.
DOUBLES
Winner (2): 2019 – Hiroshima (w/Hibino), 2014 – Istanbul (w/Svitolina).
Finalist (1): 2015 – Tokyo [Japan Open] (w/Nara).
ADDITIONAL
WTA 125K Series Titles – Singles (2): 2019 – Bastad; 2016 – San Antonio.
Japanese Fed Cup Team, 2011, 2013-15, 2017, 2019-20; Japanese Olympic Team, 2016.
| Date | Rd | Match | Score | Time |
| 2019 | F | Doi d. Danka Kovinic [MNE] | 6-4 6-4 | 01:20 |
| 2019 | SF | Doi d. (8)Aleksandra Krunic [SRB] | 6-1 7-5 | 01:22 |
| 2019 | QF | Doi d. (4)Mona Barthel [GER] | 6-2 3-6 6-2 | 01:49 |
| 2019 | R16 | Doi d. (7)Elena Rybakina [KAZ] | 4-6 6-4 6-4 | 02:00 |
| 2019 | R32 | Doi d. Alison Bai [AUS] | 6-1 6-1 | 01:00 |
