Radwanka ousted by 18-year-old Konjuh

A fearless big hitter, Ana Konjuh compiled a 38-9 edge in winners against Agnieszka Radwanska.

Ana Konjuh was the junior champion at Flushing Meadows in 2013.   -  AP

Trying to serve out the biggest victory of her career, 18-year-old Ana Konjuh was startled — right along with everyone else under the roof in Arthur Ashe Stadium — by a piercing noise coming from the U.S. Open arena's sound system during a ball toss.

The Croatian teen recoiled, let the ball drop and put her left hand to her chest. Once Konjuh realized nothing bad was going on, she smiled, then resumed playing and finished off a 6-4, 6-4 upset of No. 4 seed Agnieszka Radwanska on Monday night to reach her first Grand Slam quarterfinal.

"I just said to myself, 'Stay in the game. Don't rush'," Konjuh said.

Konjuh, who is ranked only 92nd, had never been past the third round at a major until this tournament. She was the junior champion at Flushing Meadows in 2013.

A fearless big hitter, Konjuh compiled a 38-9 edge in winners against Radwanska, who is 27 and was the runner-up at Wimbledon in 2012. Radwanska is now 0-5 in fourth-round matches at the U.S. Open, the only Grand Slam event where she hasn't been to the quarterfinals at least once.

"I just couldn't do any more, I guess, today," Radwanska said. "I was really trying. I was just too slow today."

She wondered aloud at her news conference why the match was played with the new $150 million retractable roof atop Ashe shut. A shower briefly had interrupted the previous match, Andy Murray's victory over Grigor Dimitrov, just before its final game, but then the wet weather quickly disappeared.

Before Konjuh-Radwanska began, the cover was closed atop the arena.

Asked whether she was told why by a tournament official, Radwanska said: "Well, the risk of rain. But, well, there was always risk of rain, I guess."

Would she have preferred for the match to be played without the roof?

"I don't know what would happen if that would be open. Sometimes," she added, "I just don't understand why they're closing the roof."

This year at the All England Club, Konjuh held three match points against Radwanska but lost their second-round match 9-7 in the third set after accidentally stepping on a tennis ball and injuring her right ankle during a point at 7-all.

On Wednesday, Konjuh will face 10th-seeded Karolina Pliskova, who eliminated Venus Williams in three sets. Pliskova, who is 24, has never played in a major quarterfinal, either.