In a rematch of the 2018 final, defending champion and No.4 seed Julia Goerges faces No.5 seed Caroline Wozniacki for the 11th time overall and fourth time in Auckland. Goerges leads the head-to-head 6-4 overall, and has won six of their last eight matches, including the last three in a row - but on outdoor hard courts they are tied at 3-3. The pair's Auckland tilts comprise three of their last four encounters: Wozniacki won 6-4, 6-4 in the 2015 quarterfinals, but Goerges took their 2017 quarterfinal 1-6, 6-3, 6-4 and the 2018 final 6-4, 7-6(4).
No.1 seed Serena Williams faces Laura Siegemund for the second time, having defeated the German 6-2, 6-1 in the second round of Indian Wells 2016. Siegemund is bidding for her 10th career Top 10 win, and first since she put together a run of five straight victories over Top 10 opponents across three tournaments - Charleston, Stuttgart and Madrid - in 2017. However, only one of the 31-year-old's Top 10 wins has come off clay - and that was via retirement over Timea Bacsinszky in the first round of Luxembourg 2015.
Alizé Cornet is bidding to reach her first semifinal since her run to the Lausanne final last July. The Frenchwoman beat Jessica Pegula 6-2, 6-3 in their only previous meeting, in the first round of last year's US Open. Pegula is playing her first quarterfinal since winning her maiden title in Washington last August.
No.3 seed Amanda Anisimova is aiming to make her first semifinal since Roland Garros last year in a first encounter with wildcard Eugenie Bouchard, who is seeking to reach the last four of a tournament for the first time since Luxembourg 2018. World No.262 Bouchard is one of two players ranked outside the Top 200 to have reached a quarterfinal in the first week of 2020, the other being World No.1168 Kateryna Bondarenko in Shenzhen.
ORDER OF PLAY (starts 12 noon)
Jessica PEGULA (USA) vs Alizé CORNET (FRA)
 Serena WILLIAMS (USA) vs Laura SIEGEMUND (GER)
Not before 3.30pm
 Caroline WOZNIACKI (DEN) vs  Julia GOERGES (GER)
Not before 7pm
 Amanda ANISIMOVA (USA) vs [WC] Eugenie BOUCHARD (CAN)
Serena WILLIAMS (USA) / Caroline WOZNIACKI (DEN) vs Kirsten FLIPKENS (BEL) / Alison VAN UYTVANCK (BEL)