Czech Republic’s 10th seed Karolina Muchova beat Slovakia’s Viktoria Kuzmova 7-5 6-2 to move into the second round of the Bronx Open while fourth seed Zhang Shuai was knocked out in straight sets on Monday. Muchova, who reached her first Grand Slam quarter-final at Wimbledon last month, won an incredible 93per cent of her first serve points. She did not face a single break point in the match, wrapping up the contest in 69 minutes. The 22-year-old Czech will now play American wildcard Kristie Ahn who beat Switzerland’s Jil Teichmann earlier in the day. Zhang, another Wimbledon quarter-finalist this year, was knocked out by Germany’s Andrea Petkovic, who broke the Chinese five times in a 6-3 6-4 victory. Petkovic, ranked 55 places below her opponent, regularly attacked Zhang’s second serve with powerful returns. Even though Zhang won four games in a row in the second set, she was no match for her big-hitting opponent. Coco Vandeweghe, another American wildcard who was sidelined with an ankle injury for 10 months until her return to the tour last month, was knocked out 6-3 6-0 by Russia’s Anna Blinkova. Fifth seed Katerina Siniakova advanced at the expense of Wang Yafan with a straightforward 6-3 6-2 win. Romania’s Mihaela Buzarnescu saw off the challenge of Germany’s Laura Siegemund despite dropping the opening set with a 3-6 6-0 6-4 victory.