WHAT HAPPENED: Seven years removed from her last US Open quarterfinal, qualifier Kaia Kanepi continued her improbable run to the US Open last eight, defeating 20-year-old Russian Daria Kasatkina, 6-4, 6-4.

Kanepi, now ranked world No. 418 after a rash of injuries and illness, considered quitting tennis last year only to make a roaring comeback in Flushing Meadows. Posting her seventh win over the past fortnight, she is the second qualifier to reach the quarterfinals in New York in the Open Era, after Barbara Gergen in 1981.

"I hoped to qualify and keep going, see what happens with my tennis," Kanepi said after the match. "Yeah, it's pretty amazing where I am now compared to where I was few months ago. I didn't expect me to play that well so fast after starting my comeback."

A big-hitter off the ground from both sides, Kanepi kept her younger opponent on the run for the duration of the match, stroking 34 winners to Kasatkina's 11 over the course of the 20 games.  

Kanepi fell behind an early break to begin the opening set, but leveled the match at two games apiece with precise baseline hitting that left Kasatkina scrambling. After breaking serve in a marathon game to lead 5-3, Kanepi dropped her serve at love, but made no mistake as she replied with a love break in kind, stroking a pair of winners to earn the first set.

play video Kasatkina vs. Kanepi

The second set saw Kanepi earn an early break, after saving four break points in the third game, but the young Russian worked her way back into the match after winning a titantic break with the Estonian serving at 4-2. In a nine-deuce game, Kasatkina saved eight game points to get the match back on serve, but was unable to secure momentum much further, as the match ended with four straight breaks.

"I have always loved being in New York. [Last year], I came two days to New York just to stay in the city, because I didn't play US Open last year. I wanted to be in the city," Kanepi said. "I like the atmosphere. I like being here. I love the courts and the climate, and I think that the courts suit my game really well."

WHAT IT MEANS: No stranger to the last eight of a Grand Slam, Kanepi has now reached six Grand Slam quarterfinals in her career. She in 0-5 in her previous attempts, losing in straight sets on four occasions: twice at the French Open (2008, 2012), once at the US Open (2010) and once at Wimbledon (2013). 

The lone match where Kanepi earned a set was one of the most dramatic matches of her career, as she lost to Petra Kvitova in the 2010 Wimbledon quarterfinals, 4-6, 7-6, 8-6, despite having five match points in the match. 

Whatever the result of the fourth-round match between Elina Svitolina and Madison Keys, Kanepi is guaranteed to face a seed for the first time in this tournament. 

MATCH POINT: During the most improbable of her major runs, can Kanepi finally take it one step further?