(Reuters) - Victoria Azarenka showed little sympathy against an ailing Magdalena Rybarikova as the Belarussian eased to a 6-0 6-0 victory over her Slovak opponent to book a BNP Paribas Open semi-final berth on Thursday.
The 2012 champion polished off the opening set in just 34 minutes as she raced towards a first 'double bagel' at the tournament in two years.
"I think the key was the start. I started really well and took control and I think in the second set, she wasn't really feeling well," Azarenka, who faces big-serving Czech Karolina Pliskova in the semi-finals, told reporters.
"I'm glad I stayed focused on my game."
Following the first set, the unseeded Rybarikova took a medical timeout to have her upper thigh taped.
Rybarikova was clearly struggling by the end of the match but the unseeded Slovakian was always fighting a lost cause as she had her serve broken six times and finished with 25 unforced errors.
Azarenka continues her rise up the rankings after two injury-hampered seasons and the former world number one is exuding confidence in California this week, having dropped just one set in her tournament.
A victory in the final on Sunday would be the 15th-ranked Azarenka's second tournament win of the season after her Brisbane International triumph in January. "I'm very happy to be playing and to be improving," she said. "It's a different stage of my career where I can work hard and enjoy myself. I see the potential and that's exciting."
Earlier, Pliskova enjoyed a similarly dominant victory when she cruised into the semi-finals with a 6-3 6-2 victory over Russian teenager Darya Kasatkina. Top seed Serena Williams will take on third-seeded Pole Agnieska Radwanska in Friday's other semi-final.
Pliskova blasted 30 winners and powered down nine aces to end Kasatkina's fairytale run in California, wrapping up the win in a little more than an hour at the Indian Wells Tennis Garden.
The 18-year-old Russian was unable to replicate the form she produced in ousting 12th-seeded Timea Bacsinszky in straight sets in the previous round as she was overpowered by the world number 19.
"I was really happy with the way I played, I think it was one of the best matches that I played here so far," Pliskova, 24, told reporters after reaching her first WTA 'premier mandatory' semi-final.
"I played some good tennis this week, and then there is Miami (next week), so I have chances to improve my ranking and get close to the top 10 again."
While Kasatkina's dream run at Indian Wells finally came to an end, the 48th-ranked Russian was able to reflect on her rapid improvement since this time last year when she was toiling away on the lower-tier ITF circuit.
"Now I'm (going to be) top 40," Kasatkina said of her rise up the world rankings. "Last year I was 340. Yeah, it was pretty fast!"
(Reporting by Mark Lamport-Stokes and Jahmal Corner in Los Angeles; Editing by John O'Brien)