British number one Emma Raducanu put in an impressive showing to beat Beatriz Haddad Maia 6-1 2-6 6-4 in the third round at Indian Wells.
Raducanu, 20, broke the Brazilian world number 13 twice in the first set, but dropped her serve twice.
In the decider Raducanu produced some brilliant tennis, breaking Haddad Maia in the seventh game before serving out the match in California.
She will play world number one Iga Swiatek in the last 16.
Poland's Swiatek beat Canadian Bianca Andreescu 6-3 7-6 (7-1).
"I wanted to step up and be more aggressive and, if I were to lose, then I would lose going for my shots and doing the right things," Raducanu told BBC Sport.