Play starts at 3.30pm
Caroline Garcia (FRA)  v Garbiñe Muguruza (ESP) 
Catherine Bellis (USA) v Simona Halep (ROU) 
Caroline Wozniacki (DEN)  v Angelique Kerber (GER) 
Not before 8pm
Petra Kvitova (CZE)  v Julia Goerges (GER) 
Barbora Krejcikova (CZE) / Katerina Siniakova (CZE) v Miyu Kato (JPN) / Makoto Ninomiya (JPN)
Ekaterina Makarova (RUS) / Elena Vesnina (RUS)  v Monique Adamczak (AUS) / Lyudmyla Kichenok (UKR)
Kateryna Bondarenko (UKR) / Aleksandra Krunic (SRB) v Gabriela Dabrowski (CAN) / Jelena Ostapenko (LAT)
Timea Babos (HUN) / Kristina Mladenovic (FRA)  v Andreja Klepac (SLO) / María José Martínez Sánchez (ESP) 
Petra Kvitova takes part in her fourth Doha singles quarterfinal on Friday, seeking to make if through to the last four for the first time.
Angelique Kerber faces Caroline Wozniacki for the first time since beating the Dane in the US Open semifinals in 2016. The German holds the advantage in career meetings with the current World No.1, winning eight of their 13 encounters.
Simona Halep is the only remaining former champion in the draw, and could reclaim the World No.1 spot if she lasts a round longer in Doha than current leader Caroline Wozniacki.
Julia Goerges could record her 250th main-draw career win on Friday, but faces an opponent in Petra Kvitova who has already beaten the German in 2018 - taking the honors en route to the St Petersburg title earlier this month.
Four of the eight quarterfinalists have held the World No.1 spot in the past year - Garbiñe Muguruza, Simona Halep, Angelique Kerber and Caroline Wozniacki all sharing top spot around.