No.5 seed Petra Martic defeated No.3 seed Madison Keys 3-6, 6-3, 6-1 in their only previous encounter, in the second round of Roland Garros 2017 - a significant stepping stone for the Croat in her comeback from a major back injury. Ranked World No.290 at the time, the win was Martic's first Top 20 scalp in five years and paved the way to reaching the fourth round - a Grand Slam stage she had only reached once previously, but has appeared in six times since her return.
No.7 seed Alison Riske beat No.11 seed Karolina Muchova 6-7(4), 6-3, 6-2 in the first round of 's-Hertogenbosch this year en route to claiming her second career title. That match was one of 16 three-set wins the American has scored - to only four losses - since the start of this year's grass season.
No.1 seed Kiki Bertens' round robin journey in Zhuhai has been duplicating her draw in Beijing. Three weeks ago, the Dutchwoman defeated Donna Vekic 3-6, 6-1, 7-6(3) in the first round and Dayana Yastremska 7-6(5), 6-3 in the second round on the way to the semifinals in the Chinese capital; this week, she has already reaffirmed her Vekic win 7-6(5), 6-2 and will seek to do the same against Ukrainian 19-year-old Yastremska in their second career meeting.
The match between Bertens and Yastremska will decide the semifinalist from the Azalea Group. In the Orchid and Camellia Groups respectively, both Keys and Riske need a win today to stay in the tournament.
ORDER OF PLAY (starts 1.30pm)
 Lyudmyla KICHENOK (UKR) / Andreja KLEPAC (SLO) vs  Oksana KALASHNIKOVA (GEO) / Sofia KENIN (USA)
Not before 3pm
 Madison KEYS (USA) vs  Petra MARTIC (CRO)
 Alison RISKE (USA) vs  Karolina MUCHOVA (CZE)
Not before 7pm
 Kiki BERTENS (NED) vs  Dayana YASTREMSKA (UKR)