Emma Raducanu earned a 6-2 6-3 win against qualifier Rebeka Masarova in the first round at Indian Wells.
The Briton broke the Spaniard's serve twice to go 3-0 up, but a third double fault from Raducanu allowed Masarova to pull a game back.
Raducanu went 0-40 down when 5-2 in front but recovered to serve out for the first set in 43 minutes.
She struggled on her serve at times but won the second set to book a meeting with Ukraine's Dayana Yastremska.
More to follow.