Serena Williams was the defending champion, and successfully defended her title, defeating lucky loser CoCo Vandeweghe in the final, 7–5, 6–3. It was the first all-American final on the WTA Tour since the 2009 WTA Tour Championships, and the first on American soil since Los Angeles in 2004.
Camila Giorgi was the defending champion of the 2016 Ricoh Open, but withdrew before the tournament began.
Yanina Wickmayer was the defending champion, but lost in the first round to Viktorija Golubic.
This is the first edition of the tournament.
The 2017 Ricoh Open was a tennis tournament played on outdoor grass courts. It was the 28th edition of the Rosmalen Grass Court Championships, and part of the 250 Series of the 2017 ATP World Tour, and of the WTA International tournaments of the 2017 WTA Tour. Both the men's and the women's events took place at the Autotron park in Rosmalen, 's-Hertogenbosch in the Netherlands, from June 12 through June 18, 2017.
The 2017 Ricoh Open was a tennis tournament played on outdoor grass courts. It was the 28th edition of the Rosmalen Grass Court Championships, and part of the 250 Series of the 2017 ATP World Tour, and of the WTA International tournaments of the 2017 WTA Tour. Both the men's and the women's events took place at the Autotron park in Rosmalen, 's-Hertogenbosch in the Netherlands, from June 12 through June 18, 2017.
The singles final of the Stanford Classic was held on August 6, 2017. Johanna Konta was the defending champion, but chose not to participate this year. Madison Keys won the title, defeating CoCo Vandeweghe in the final, 7–6(7–4), 6–4.
Markéta Vondroušová was the defending champion, but lost in the second round to Elise Mertens.
Mona Barthel was the defending champion, but lost in the first round to Antonia Lottner.
Anett Kontaveit was the defending champion, but lost in the first round to Veronika Kudermetova.
Caroline Wozniacki was the two-time defending champion, but lost in the second round to Camila Giorgi.
Polona Hercog defeated Iga Świątek in the final, 6–3, 3–6, 6–3 to win the women's singles tennis title at the 2019 Ladies Lugano Open. It was Świątek's first WTA Tour final.
Petra Kvitová was the defending champion, but chose not to participate this year.
Alison Riske defeated Kiki Bertens in the final, 0–6, 7–6(7–3), 7–5, to win the women's singles title at the 2019 Rosmalen Grass Court Championships. Riske saved five championship points en route to winning her second career WTA Tour singles title, her first in five years.
This was the first edition of the event.
Ashleigh Barty defeated Aryna Sabalenka in the final, 3–6, 6–0, 6–3 to win the women's singles tennis title at the 2021 Stuttgart Open. It marked her 11th career Women's Tennis Association (WTA) singles title and her second on clay. She became the first reigning world No. 1 to win the title since Justine Henin in 2007.
Liudmila Samsonova defeated Belinda Bencic in the final, 1–6, 6–1, 6–3, to win the singles tennis title at the 2021 WTA German Open. Samsonova was contesting her first career final on the WTA Tour and had entered the main draw as a qualifier. Her win made her the 10th maiden titlist on the 2021 WTA Tour and the second qualifier of the season to claim a title.
This is the first edition of the event as a WTA 125 tournament. It was part of the ITF Women's Circuit from 2016 to 2018. Viktória Kužmová was the champion when the event was last held in 2018, but lost in the first round of qualifying to Amarissa Kiara Tóth.
Anna Blinkova defeated Jasmine Paolini in the final, 6–2, 3–6, 6–2 to win the singles tennis title at the 2022 Transylvania Open. It was her maiden WTA Tour singles title, and she won it as a qualifier.
Vitalia Diatchenko was the defending champion but withdrew before the tournament began.
Anett Kontaveit 
Natalia Vikhlyantseva 
