Last week's ATX Open champion Marta Kostyuk was bundled out in the Indian Wells Open first round by last month's Merida Open runner-up Rebecca Peterson on Wednesday.

The Swedish qualifier, who reached her first WTA final in four years in Merida having had her 2022 derailed by injury, triumphed 7-5 5-7 7-5 over the Ukrainian world number 40 in almost three hours.

Kostyuk, ranked 40th in the world, was not helped by 17 double faults across the match, with Peterson progressing to the second round where she will face 22nd seed Zhang Shuai.

Alize Cornet was also a surprise first-round loser, going down 6-2 7-5 to 427th-ranked Evgeniya Rodina in one hour and 42 minutes.

Rodina's prize for her shock victory is a second-round date with 2023 Australian champion and second seed Aryna Sabalenka.

Camila Giorgi, who beat Peterson for the aforementioned Merida Open crown last month, won through with a routine 6-3 6-3 victory over Arantxa Rus. Giorgi will next face third seed Jessica Pegula.

World number 41 Shelby Rogers was pushed for two hours and 22 minutes by Katie Volynets but triumphed 6-4 4-6 6-1. Rogers will take on seventh seed Maria Sakkari in the second round.

China's Wang Xin, making her Indian Wells debut, defeated former world number 12 Elise Mertens 6-3 6-1, while world number 33 Zhu Lin was downed by Lesia Tsurenko 6-4 6-3.

Aliaksandra Sasnovich won 6-3 7-6 (7-5) over veteran Kaia Kanepi, while 53rd-ranked Linda Fruhvirtova fought back after copping a bagel to win 0-6 6-2 6-3 over 52nd-ranked Mayar Sherif.

Jil Teichman set up a second-round clash with Swiss compatriot Belinda Bencic after a 6-1 6-4 victory over Ashlyn Krueger.