INDIAN WELLS - Russian Daria Kasatkina, who has beaten all four reigning Grand Slam champions in the past year, upset world No. 2 Caroline Wozniacki 6-4, 7-5 at the WTA Indian Wells event on Tuesday (early on Wednesday morning, outh African time).
Kasatkina recorded her second straight win over Wozniacki, having also beaten the reigning Australian Open champ at the St. Petersburg tournament last month.
The 20-year-old Kasatkina improved to 11-6 on the WTA Tour season as she seeks to better her quarter-final appearance here in 2016.
Kasatkina hit one ace, won 54 percent of her first serves and broke Wozniacki's serve six times in the one hour, 40 minute match.
"She outsmarted me today, which is fair enough," Wozniacki said. "But, you know, at least I tried, and I tried to do what I thought I needed to do out there today.
"I just couldn't execute as well as I wanted to."
It was a disappointing exit for Wozniacki, who finally silenced her critics earlier this year with her maiden Grand Slam title in Melbourne, where she defeated Simona Halep in the final.
That victory not only earned Wozniacki her first Grand Slam title but it made her the world number one. Halep reclaimed the ranking just before Indian Wells.
Wozniacki had a chance to take it back but she needed to win the Indian Wells title to do it.
Kasatkina will play either seventh seed Caroline Garcia of France or Angelique Kerber of Germany in the quarter-finals.
Halep eases into fifth round
Earlier, Halep breezed through her fourth round match on with a 7-5, 6-1 victory over China's Wang Qiang.
Halep, who is one of two former champions left in the draw, is now 17-1 on the season having already won a title in both singles and doubles at Shenzhen, China.
Halep advances to the quarter-finals where she will face unseeded Petra Martic of Croatia who beat Czech Marketa Vondrousova 6-3, 7-6 (7/4).
Halep called for a timeout in the first set so her coach Darren Cahill could come down to the court to discuss strategy.
"It was really important, because he just told me what I have to do. I knew that I had to change something, but I didn't realize what it was exactly," she said.
"So it was a good chat. I did exactly what he said after that."
Halep needed just 76 minutes on the main stadium court to dispatch Wang as she won 64 percent of her first-serve points and broke Wang's serve seven times.
Halep said she is happy with the way she is playing at this stage in the tournament. "I am confident. I am feeling the game," she said.
Wang was the last Chinese player standing in the California desert, having achieved a career best result in Indian Wells by reaching the round of 16.
Tuesday's quick victory came two days after Halep needed over two hours to eliminate American teenager Caroline Dolehide 1-6, 7-6 (7/3), 6-2.
"The previous match was really tough for my body," said Halep, who missed some time this year with a right foot injury.
"I stayed so many weeks off with injury and now coming back, so I was a little bit tired.
"I missed too many shots in the first set. And then I just got the idea of what I have to do to play against her, and it was much easier."
Venus moves on
Meanwhile, Williams survived a difficult fourth round test to beat Sevastova just one day after beating sister Serena for the first time since 2014 in Montreal.
Williams, who is the oldest female player in the draw at 37, rallied back in the second set to book her spot in the quarter-finals.
She next faces either wild card Danielle Collins or world number 27 Carla Suarez Navarro of Spain.
The 25-year-old Czech Pliskova blasted four aces and broke Anisimova's serve three times in the one hour, 32 minute match.
Pliskova advances to the quarter-finals where she will face Naomi Osaka of Japan who beat unseeded Maria Sakkari 6-1, 5-7, 6-1.