Linz champion Coco Gauff makes her ASB Classic debut in a first meeting against Viktoria Kuzmova, who reached her third and most recent career semifinal at this tournament last year. 15-year-old Gauff is the youngest player in the draw.
Caroline Wozniacki becomes the first woman to play doubles with both Serena and Venus Williams when she partners Serena against Nao Hibino and Makoto Ninomiya today. The Dane previously reached the second round of Doha 2008 alongside Venus, defeating Vera Dushevina and Elena Likhovtseva before falling to Latisha Chan and Chuang Chia-Jung. This will be the fourth time Serena has partnered a player other than Venus in her career, having reached the Tokyo 2002 quarterfinals with Martina Navratilova, won Leipzig 2002 with Alexandra Stevenson and lost one Fed Cup rubber with Alison Riske in 2015.
Two former Top 10 players clash as Daria Kasatkina takes on Carla Suárez Navarro, who is embarking on the final season of her career. Kasatkina won their only previous meeting 6-1, 6-2 in the 2015 Moscow quarterfinals - the Russian's first career Top 20 win to reach her first career WTA semifinal.
No.8 seed Caroline Garcia will bid to put a poor second half of 2019 behind her as she takes on Taylor Townsend for the first time today. After winning Nottingham and reaching the Mallorca quarterfinals in June, the Frenchwoman went just 5-13 over the rest of the year, and is currently on a three-match losing streak - including a first-round defeat by Pauline Parmentier as the No.2 seed in the Limoges 125K last month. Townsend, meanwhile, has played just one event since her breakthrough US Open fourth-round run, which featured an upset of Wimbledon champion Simona Halep, reaching the Houston 125K quarterfinals in November.
Catherine Bellis plays her first WTA main draw since Miami 2018 in a first meeting with fellow American Jessica Pegula today. Bellis, who has undergone four surgeries due to wrist and elbow injuries, ended a 20-month layoff at the Houston 125K in November, qualifying and reaching the third round.
Kirsten Flipkens will bid to extend a five-match winning streak against wildcard Eugenie Bouchard. The Belgian, who won the Houston 125K event to end her 2019 season, was also triumphant in her only previous meeting with Bouchard, winning 7-5, 3-6, 7-5 in the first round of Indian Wells last year.
In qualifying, 2017 Wimbledon junior runner-up Ann Li bids to make her first WTA main draw against fellow American Usue Maitane Arconada. Li was victorious in both of their previous encounters, both in US ITF World Tour events last year.
ORDER OF PLAY
STADIUM (starts 3pm)
Taylor TOWNSEND (USA) vs  Caroline GARCIA (FRA)
Coco GAUFF (USA) vs Viktoria KUZMOVA (SVK)
Serena WILLIAMS (USA) / Caroline WOZNIACKI (DEN) vs Nao HIBINO (JPN) / Makoto NINOMIYA (JPN)
[WC] Eugenie BOUCHARD (CAN) vs Kirsten FLIPKENS (BEL)
GRANDSTAND (starts 11am)
Qualifying - Catherine MCNALLY (USA) vs Varvara LEPCHENKO (USA)
Qualifying - Isabella SHINIKOVA (BUL) vs  Greet MINNEN (BEL)
Not before 2pm
Carla SUÁREZ NAVARRO (ESP) vs Daria KASATKINA (RUS)
Jil TEICHMANN (SUI) vs [WC] Valentina IVANOV (NZL)
[WC] Sara ERRANI (ITA) / Paige Mary HOURIGAN (NZL) vs Jessica MOORE (AUS) / Arina RODIONOVA (AUS)
COURT 1 (starts 11am)
Qualifying - Usue Maitane ARCONADA (USA) vs Ann LI (USA)
Qualifying -  Camila GIORGI (ITA) vs  Ysaline BONAVENTURE (BEL)
Not before 2pm
Catherine BELLIS (USA) vs Jessica PEGULA (USA)
 Rebecca PETERSON (SWE) vs Tamara ZIDANSEK (SLO)
 Desirae KRAWCZYK (USA) / Laura SIEGEMUND (GER) vs Irina BARA (ROU) / Valeria SAVINYKH (RUS)