The Belarusian says she owes Swiatek gratitude, and looks forward to more battles with her.
"I think [Madison Keys is] a bigger hitter on tour than a Sabalenka or an Iga or even a Rybakina," said Jessica Pegula.
"I knew since he started to play on tour that he have amazing serve," Andrey Rublev said of Ben Shelton.
Wimbledon champion withdrew from US Open doubles to save her stiff shoulder for singles quarterfinal vs. Madison Keys.
The Pole is sad about losing her US Open title defense and the No.1 ranking, but believes she'll be back.
The Romanian is the oldest woman to ever reach her first US Open quarterfinal.
"Every match I played here, I played a little bit better each time. A lot of positives I can bring with me," Caroline Wozniacki said.
