NEW YORK (AP) — Alison Riske started the summer with a long list of nevers on her resume.
Never won a match at a Grand Slam tournament or at a hard-court WTA Tour event. Never defeated a top- 10 foe or cracked the top 100 of the rankings.
She's now achieved all those things, her latest breakthrough victory a rout of 2011 Wimbledon champ Petra Kvitova to reach the round of 16 at the U.S. Open. Riske won 6-3, 6-0 on Saturday, taking the last eight games against the seventh-seeded Czech, who was in bed with a fever the day before.
"I've got a new confidence in myself," the 23-year-old American said through tears during an on-court interview. "I believe that I belong here."
Riske was 0-5 at major tournaments before Wimbledon this year but is 5-1 since. After breaking into the top 100 in late July, she now likely will earn a top-60 ranking. She's currently 81st.
"It's really tough out here," she said. "Every week isn't like this."
She has always thrived on grass, making the third round at Wimbledon this year. Now the Pittsburgh native is starting to figure out the hard courts. She next faces an unseeded opponent, Daniela Hantuchova.
Kvitova said she tried to end points quickly, knowing she couldn't hold up through long rallies. But Riske stayed calm and played good defense, taking advantage of Kvitova's seven double-faults and 27 unforced errors.
"She moved quite well," Kvitova said. "She pushed me to the back. That was tough for me."
It's another frustrating finish at Flushing Meadows, the only major tournament where Kvitova hasn't made the semifinals. Two years ago, she became the first reigning Wimbledon women's champion to lose her first U.S. Open match in the same season.
Kvitova will drop out of the top 10 for the first time since May 2011.
"My body wouldn't let me fight," Kvitova said.
Riske joins Serena Williams and Sloane Stephens in representing the U.S. in the round of 16. It's the first time since 2004 that two American women not named Williams advanced this far in this event. Jennifer Capriati and Lindsay Davenport, along with Venus and Serena, made it to the fourth round that year.
Riske was all set to play for Vanderbilt in 2009 when a family friend who owns a chemical company offered to sponsor her. So she turned pro.
A year ago at this time, she was questioning the wisdom of that decision. Then she rejoined coach Yves Boulais.
"Once I got back with him, things kind of unfolded themselves," Riske said. "I felt really comfortable. I knew that with the tennis I was playing that things were going to start coming together. I just didn't know when."