Madison Keys sent top-seeded Iga Swiatek packing on Thursday with a stellar 6-3, 6-4 victory to reach the quarterfinals of the Western Southern Open at Mason, Ohio.

Keys won nine consecutive games at one point at the Cincinnati-area event while thoroughly outplaying Swiatek, who has struggled since winning the French Open in the spring.

The result also was stunning. When Swiatek and Keys met in the Indian Wells quarterfinals in March, the Polish standout rolled to an easy 6-1, 6-0 victory.

It was a total turnaround in this meeting, which marked Keys' first win against Swiatek in three meetings.

"I'm going to be totally honest," Keys said. "After I got two games, I was like, 'OK, it's better than last time. It's fine.'

"Honestly, that really just made me relax, but I think also this is the first time we have played on a faster court so I definitely felt more comfortable with the conditions just from the start. I think I settled in pretty quickly."

Keys' nine-win run gave her a 5-0 lead in the second set. Swiatek fought back by winning the next four games before Keys closed out the straight-sets win.

"I was really just thinking that I had to focus a lot on why I got in the position of being up 5-Love," Keys said. "I think I backed off a little bit, and I think she started playing better."

Keys had a 14-6 edge in winners and both players committed 14 unforced errors in the 85-minute match.

Keys next faces Elena Rybakina of Kazakhstan. The Wimbledon champion had nine aces while rolling to a 6-2, 6-4 victory over Alison Riske-Amritraj.

Second-seeded Anett Kontaveit of Estonia and fifth-seeded Ons Jabeur of Tunisia joined Swiatek in the elimination line.

China's Shuai Zhang rallied for a 2-6, 6-4, 6-4 upset of Kontaveit, while Czech Petra Kvitova knocked off Jabeur 6-1, 4-6, 6-0.

Also, France's Caroline Garcia ousted Elise Mertens of Belgium 6-4, 7-5.