Konjuh stuns Radwanska

New York: Croatian teen Ana Konjuh upset fourth seed Agnieszka Radwanska 6-4, 6-4 on Monday to claim the last women's quarterfinal spot at the US Open. The 18-year-old, who won the 2013 US Open juniors title after claiming the Australian Open junior’s crown, lost her first service game but did not yield serve again.

She cracked 38 winners, including six aces, against the Pole, who has never gone beyond the round of 16 in five attempts at Flushing Meadows. The power-hitting teenager, who became the first Croatian woman to reach the quarterfinals at a US Open, avenged a second-round loss to Radwanska at Wimbledon, where she held three match points before falling 9-7 in the third set. “It's been an incredible night,” Konjuh said.

Serena Williams defeated Yaroslava Shvedova 6-2, 6-3 to become more victories in Grand Slam matches than Roger Federer with her 308th. In the men’s pre-quarterfinal, second seeded Murray thrashed Bulgarian 22nd seed Grigor Dimitrov, winning in three sets 6-1, 6-2, 6-2 and joined Swiss third seeded Stan Wawrinka, Japanese sixth seeded Kei Nishikori and Argentine Juan Martin del Potro.

Murray needed only two hours on the Arthur Ashe Court to beat Dimitrov. Japanese 26-year-old fourth seed Kei Nishikori won in three sets 6-3, 6-4, 7-6 against twenty-first seeded Croatian Ivo Karlovic. It was a David and Goliath clash of physical opposites, but the 6-foot-11 (2.11 m) Karlovic's tennis game, apart from his prodigious serve, was overshadowed by the skills of Nishikori, more than a foot shorter at 5-10 (1.78 m).

Before the triumphs of Nishikori and Murray, Wawrinka has also reached the quarters for the fifth time, his fourth time in a row, beating Illya Marchenko from Ukraine 6-4, 6-1, 6-7 (5), 6-3. Del Potro will face Wawrinka in the quarters, after his eighth seeded Austrian rival Dominic Thiem withdrew while trailing 3-6, 2-3 in the second set with a right knee pain despite receiving assistance from the physiotherapist.