Ajla Tomljanovic has recorded her first win over a top-10 opponent this year and fourth of her career, upsetting Garbine Muguruza to reach the last 32 of the WTA Tour event in Indian Wells.
The Australian sent world No.6 Muguruza packing 6-3 1-6 6-3 to set up a meeting with French Open semi-finalist Tamara Zidansek.
Coming into the match with an 0-6 record in 2021 against players in the top 10, Tomljanovic showed few signs of nerves as she powered through the opening set - breaking serve three times.
She did not let a mid-match hiccup derail her chances as she broke in the opening game of the deciding set to grab the momentum.
While fifth-seeded Muguruza got back on level terms at 3-3, Tomljanovic regrouped immediately to break serve and then did so again in the final game of the match to secure victory.
Muguruza won her ninth career singles title in Chicago last week but in California it was Tomljanovic who won the important points in their one hour and 52 minutes encounter.
Tomljanovic is now 2-3 against Muguruza after snapping a three-match losing streak to the Spanish former world No.1.
"I was really looking forward to playing Garbine because I did lose last couple of times but I did try to focus on that one time I beat her and channel that energy, so I was really happy I got through today," Tomljanovic said in a post-match interview.
Fellow Australian Astra Sharma was forced to retire when leading Daria Katsakina 4-3 in the first set, ending a run that began in qualfying.
No.12 seed Ons Jabeur, who lost to Muguruza in the Chicago final, advanced with a 6-2 6-7 (7-5) 6-3 win over Anastasija Sevastova for her Tour-leading 45th match victory of the year.
Coco Gauff, seeded 15th, outlasted Caroline Garcia 6-3 6-7 (7-22) 6-1, offsetting 12 aces with seven double faults.
Top seed Karolina Pliskova made light work of her opening match of the week by dispatching Magdalena Frech 7-5 6-2.
Others to progress from the second round included Amanda Anisimova and Anna Kalinskaya, who both accounted for seeded players.