Kerber, former world No.1 relegated to 607th rank, beat the Russian Veronika Kudermetova (N.19) 6-4, 7-5 and will face in the next round either the American Katie Volynets or the Danish Caroline Wozniacki, other champion (a Grand Slam title) returned from maternity last summer.

Winner of the Australian Open (2016), Wimbledon (2018) and the US Open (2016), Kerber took a break of a year and a half between the summer of 2022 and her resumption in early January during the United Cup.

Defeated in the first round of the Australian Open then the WTA 500 in Linz (Austria), she has just had three successes in California, including one against world number 10 Ostapenko in the 2nd round.

Former Japanese world No.1 Naomi Osaka, who also returned to the high level in January after giving birth to a daughter, will play her third round on Monday against Belgian Elise Mertens.