Former Indian Wells champion Victoria Azarenka cruised into the Round of 16 following a tense 7-5, 6-4 victory over rival Petra Kvitova, upsetting the No. 7 seed to claim their ninth career meeting. In 1 hour and 49 minutes, there was little to separate the two major champions in the stat line as there was on the scoreboard: Azarenka hit 25 winners, and nine aces, to 18 unforced errors, and went 6-for-11 on breakpoints. Needing treatment on her right thigh in the match, Kvitova struck 29 winners to 26 unforced, but only went 4-for-12 on breakpoints in her last match of the season.
The two-time major-winner next faces her fellow Belarusian Aliaksandra Sasnovich for a place in the last eight.
In the late-night match in the Californian desert, the US Open finalist Leylah Fernandez rallied from a set and a break down to defeat No.9 seed and French Open finalist Anastasia Pavlyuchenkova, 5-7, 6-3, 6-4 to advance to the Round of 16 in her tournament debut.
The win extended the Canadian's winning streak against Top 20 opponents to five, including wins over Naomi Osaka, Angelique Kerber, Elina Svitolina, Aryna Sabalenka, and now Pavlyuchenkova.
There could only be one winner in the third round match between two of 2021's major finalists, and Fernandez came from 7-5, 2-0 down to book a meeting with American Shelby Rogers for a place in the quarter-finals.
Earlier in the day, Aliaksandra Sasnovich backed up her upset win over Emma Raducanu in the second round with an impressively clinical 7-5, 6-4 win over 2015 champion Simona Halep on Stadium 2.
Elsewhere, Shelby Rogers continued her fine form to cap of the 2021 season, consolidating her two impressive early-round wins with a 6-0, 6-2 victory of Irina-Camelia Begu.