Konjuh, 18, in 1st Slam quarters after shock win

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 US Open arena's sound system during a ball toss.

The Croatian 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, just as calm and collected as ever, and finished 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.