Tenth-seeded Czech Karolina Pliskova brushed aside Croatian upstart Ana Konjuh 6-2, 6-2 to advance to the US Open semi-finals, the first time she has reached the final four of a Grand Slam tennis event.The 24-year-old Pliskova will next take on American World No.1 and six-time champion Serena Williams who defeated Romanian Simona Halep, reports Efe.The Czech No.11, one of the best servers on the women's tennis tour, used that weapon to full effect against Konjuh here on Wednesday, winning 92 percent of her first-serve points and 77 percent of her second-serve points over the course of the match.Pliskova, who saved a match point in her fourth-round 4-6, 6-4, 7-6 (7-3) victory Monday over American No.6 seed Venus Williams, needed just 57 minutes against Konjuh to show that her time has come to join the elite of women's tennis."I wasn't at my best level today for sure, but she was just too good. Her serve is just too good. Today on the court, you know, she found her rhythm and took the opportunities that I gave her," Konjuh said in a post-match press conference.