Top seed Madison Keys and former world No. 1 Venus Williams were the biggest casualties on a day of upsets at the WTA Charleston clay court event in South Carolina Wednesday. Keys was bundled out 4-6, 6-1, 6-1 by fellow American Shelby Rogers, who grew up in Charleston and delighted her home crowd with an aggressive performance that overwhelmed her compatriot. "It's really hard to explain," Rogers said in an on-court interview. "I've played here so many years in a row, and it's not always easy. "I feel like I've learned a lot of lessons and I've grown up right here in front of this crowd. It's so special," the 24-year-old added. Rogers will face Naomi Osaka in the next round after the Japanese player knocked out number 13 seed Zhang Shuai 6-4, 6-4 earlier in the day. Elsewhere, Venus Williams was left baffled after losing a punishing three-set, second-round battle to Germany's Laura Siegemund. The veteran third seed bowed out in her opening match of the tournament, losing 6-4, 6-7 (3/7), 7-5 to the 29-year-old world number 37. It was Siegemund's second three-setter of the tournament, and the German admitted she was as surprised as anyone following a win in which she saved two match points. "I have no idea!" Siegemund told an interviewer when asked to explain her victory. "It was a really good match; it was going up and down. I just tried to believe in my game, and if I was down, I told myself I was going to get more chances." Williams admitted she had been unable to shake off Siegemund. "I tried my best to think this could be the best match she'll ever play in her life, honestly," Williams said. Djokovic opens against Ramos Vinolas Returning to the court after an elbow injury, Novak Djokovic will play Albert Ramos Vinolas in Friday's opening singles match when Serbia meets Spain in the Davis Cup quarterfinals. Thursday's draw also pits Viktor Troicki against Pablo Carreno Busta in the best-of-five series played on an indoor hard court in the Serbian capital. On Saturday, the doubles will feature Nenad Zimonjic and Troicki against Marc Lopez and Jaume Munar. Reverse singles are scheduled for Sunday. Djokovic has dropped from his No. 1 ranking after a slump in form following his French Open title last year. He withdrew from Miami Open because of a lingering right elbow injury. Spain will be without its two top-ranked players, Rafael Nadal and Roberto Bautista Agut. A barrage of aces can be expected in the second rubber of Australia's Davis Cup quarterfinal against the United States in Brisbane Friday after Nick Kyrgios was drawn to play John Isner in singles. Australian Kyrgios, who has beaten Novak Djokovic twice and taken Roger Federer close over the last month on the back of some brilliant serving, is tied for third place with the tall American on the ATP leaderboard with 218 aces this season. The clash between world No. 16 Kyrgios and the 23rd ranked Isner will follow Jack Sock's first meeting with 22-year-old Australian Jordan Thompson on the hardcourt of the Pat Rafter Arena. Another Australian big server, Sam Groth, will team up with John Peers to take on Sam Querrey, who is no slouch in the service department, and Steve Johnson in Saturday's doubles before the reverse singles on Sunday. — Agencies
