British number three Harriet Dart is into the second round at Indian Wells after her opponent Ana Konjuh retired injured.
The 25-year-old, who came through qualifying at the California event, was leading 6-1 3-1 when Croatia's Konjuh pulled out.
She will next face Ukrainian Elina Svitolina on Friday.
Fellow British qualifiers Heather Watson and Katie Boulter play on Thursday.
British number one Emma Raducanu has a first-round bye.
In the men's draw, Liam Broady successfully came through qualifying and will play Miomir Kecmanovic of Serbia.
It means there are eight British players in the main draws.
And Andy Murray now knows his first round opponent - Japanese qualifier Taro Daniel, who beat him at the Australian Open.