Two-time Indian Wells champion Serena Williams resumes a high-profile rivalry with 2017 quarterfinalist Garbiñe Muguruza, which the American leads 3-2. Their last two encounters were both major finals - Wimbledon 2015, won by Williams 6-4, 6-4, and Roland Garros 2016, won by Muguruza 7-5, 6-4; in fact, today's match will be the first time the pair have faced each other outside a Grand Slam. Williams was also the victor in both of their prior hard court meetings, 6-2, 6-0 in the second round of the 2013 Australian Open and 2-6, 6-3, 6-2 in the fourth round of the 2015 Australian Open - the latter being their only three-setter to date. Muguruza will be bidding for her first Top 10 win in over a year, since defeating Caroline Garcia in last year's Dubai quarterfinals.

Johanna Konta leads the head-to-head against No.7 seed Kiki Bertens 2-1. The pair faced each other twice in 2012, with Bertens winning 3-6, 6-3, 7-6(6) in the quarterfinals of the ITF W25 event in Bath (and eventually taking the title) and Konta avenging the loss 6-2, 6-1 in Copenhagen en route to qualifying for her second career WTA main draw. Five years on, the Briton would also win their only previous outdoor hard court encounter 6-3, 6-3 in the second round of Cincinnati in 2017. Having gone winless against Top 10 opposition in 2018, Konta is now bidding for her second consecutive Top 10 scalp following her upset of Sloane Stephens in Brisbane.

For the second year in a row, Wang Qiang and Elise Mertens square off in Indian Wells. The Chinese No.1 owns a 2-0 head-to-head lead, having won both last year's second-round match and their 2016 Quanzhou ITF W50 quarterfinal by identical 4-6, 6-3, 6-3 scorelines.

Qualifier Stefanie Voegele and wildcard Bianca Andreescu have both won consecutive main draw matches at Premier Mandatory level for the first time this week - Voegele in her 13th appearance at this level and Andreescu on her debut - and will face each other for the first time in a bid for a maiden fourth-round showing.

No.22 seed Jelena Ostapenko's only previous encounter with Marketa Vondrousova was in the 2014 Wimbledon junior semifinals, which the Latvian took 6-1, 6-2 en route to the title. Ostapenko is bidding to make the fourth round in Indian Wells for the first time; Vondrousova reached that stage on her debut last year.

No.6 seed Elina Svitolina and Daria Gavrilova will take each other on for the eighth time today. Svitolina leads the head-to-head 5-2, having captured the last four of their encounters for the loss of just one set - in the third round of Miami last year, which the Ukrainian eventually won 4-6, 6-0, 6-1. Svitolina was also the victor of their only previous Indian Wells match, 6-2, 6-1 in the 2017 third round. Gavrilova is seeking her 12th career Top 10 scalp, and first since defeating Petra Kvitova 6-2, 6-1 in Beijing last year.

ORDER OF PLAY (all courts start 11am)

[Q] Kateryna KOZLOVA (UKR) vs Simona HALEP (ROU) [2]
After 1 ATP match
Garbiñe MUGURUZA (ESP) [20] vs Serena WILLIAMS (USA) [10]
After 1 ATP match, not before 8pm
[WC] Jennifer BRADY (USA) vs Ashleigh BARTY (AUS) [12]

After 1 ATP match
Kiki BERTENS (NED) [7] vs Johanna KONTA (GBR)
After 1 ATP match, not before 6pm

Elise MERTENS (BEL) [16] vs WANG Qiang (CHN) [18]

After 2 ATP matches
Marketa VONDROUSOVA (CZE) vs Jelena OSTAPENKO (LAT) [22]
[WC] Bianca ANDREESCU (CAN) vs [Q] Stefanie VOEGELE (SUI)

After 1 ATP match
Lyudmyla KICHENOK (UKR) / Nadiia KICHENOK (UKR) vs CHAN Hao-Ching (TPE) / Latisha CHAN (TPE) [8]
Kirsten FLIPKENS (BEL) / Johanna LARSSON (SWE) vs Darija JURAK (CRO) / Raluca OLARU (ROU)

After 1 ATP match
Raquel ATAWO (USA) / Katarina SREBOTNIK (SLO) vs Elise MERTENS (BEL) / Aryna SABALENKA (BLR)