Victoria Azarenka crushed Christina McHale 6-0 6-0 to book her place in the quarter-finals of the WTA Qatar Open.
The world number one needed just 67 minutes to see off her American opponent, converting six of her 10 break-point opportunities to remain on course to defend her title in Doha.
McHale did not play as badly as the final scoreline suggests, though she did produce three double faults in the last game to seal her exit from the event.
"Everything was working for me today," Azarenka, who will face Italian Sara Errani next, said afterwards.
"When I stepped on court I felt my game. When I had a couple of difficult games I stayed focussed and took advantage of that, and that was the key.
"Christina has played some excellent matches and had some big wins and so I had to stay focussed. I think I got rid of my frustrations (with the windy weather) yesterday."
Elsewhere, Caroline Wozniacki had to overcome strong winds on an outside court and the determined challenge of Mona Barthel to reach the last eight.
The Dane trailed 5-3 in the first set tie-break but fought back to secure a 7-6 (8/6) 6-3 victory.
Agnieszka Radwanska will be next for Wozniacki, the fourth-seeded Pole having recorded a 6-1 7-6 (8/6) win over Ana Ivanovic, the former French Open champion from Serbia.
Meanwhile, Maria Sharapova is also through to the last eight after seeing off world No 24 Klara Zakopalova in straight sets.
In a contest that featured nine breaks of serve, the No 3 seed posted a 6-3 6-3 victory over her 30-year-old opponent from the Czech Republic.
The match was much closer than the scoreline suggests, with the opening game on Sharapova's serve needing 16 points before the Russian was able to hold.
In all, Sharapova won five of her service games after facing break points against, and she finally crossed the finishing line after 88 minutes on court.
She now meets the No 8 seed Sam Stosur of Australia who ended the challenge of Russia's two-time Grand Slam champion Svetlana Kuznetsova 6-4 7-5.