Title defenses are hard to come by in Tennis Paradise. According to the history books, they are even harder for the women. Not since 1991, when legendary Martina Navratilova won her second of two titles in the California desert, has a woman managed to complete a successful singles title defense.

The streak continues.

Defending champion Mirra Andreeva was knocked out of the draw by Katerina Siniakova of Czechia in Stadium 1 on Monday, 4-6, 7-6(5), 6-3. Last year’s champion, who won by a 6-0, 6-0 scoreline in her first match of the tournament, was riding a seven-match winning streak into Monday's match. She battled ferociously, but couldn’t hold off the 44th-ranked Czech, who also happens to be a ten-time women’s doubles Grand Slam champion.

“I’m really emotional right now,” Siniakova said after reaching the round of 16 at Indian Wells for the first time. “I don’t feel any part of my body. I just kept fighting – I don’t believe it, I don’t know what to say.”

In a back-and-forth tussle that took two hours and 48 minutes to complete, Siniakova won her second consecutive marathon. Her three-hour, 28-minute win over Leylah Fernandez in the second round is the second-longest Tour-level match of the year.

The outcome hung in the balance until the bitter end, as both players converted seven breaks of serve, with a total of 42 break point opportunities (26 for Andreeva and 16 for Siniakova) between them.

In the end it was 29-year-old Siniakova who secured the final break for 5-3 in the decider. She then saved three break points before closing out the match on her first match point.

She will face either Elina Svitolina or Ashlyn Krueger in the round of 16.