Former champion Naomi Osaka said her Indian Wells first-round exit was "a little bump in the road" after losing to Camila Osorio.
Japan's Osaka, playing her first match since retiring injured from January's Australian Open, lost 6-4 6-4 to the Colombian.
The four-time major champion has had several injury struggles since returning from maternity leave in January 2024.
"There were certain things that felt extremely off because I could only start to practice serving after a certain amount of time," said Osaka, the 2018 champion.
"I think given the situation, it wasn't that terrible.
"It just feels like a little bump in the road."
Osorio, who had never previously won a match at Indian Wells, will face Denmark's Clara Tauson in the second round.
Elsewhere on the first day of main-draw action, two-time Wimbledon champion Petra Kvitova was beaten 4-6 6-3 6-4 by France's Varvara Gracheva.
The defeat means Czech Kvitova is still searching for her first win since returning to the WTA Tour last month after giving birth to her first child last July.
"If you let me step back a little bit, I really want to congratulate her," Gracheva said of Kvitova.
"I'm so happy that she now has the role of a mother and a tennis player, which is very demanding. It's just amazing."