The Australian Open preparations of Serena Williams suffered a potentially significant blow when she was forced to retire with a knee injury during the United States' 3-0 Hopman Cup loss to Australia Gold Tuesday evening. The world No. 1 retired due to soreness in her left knee during her singles match against Jarmila Wolfe (nee Gajdosova) when trailing 7-5, 2-1. Veteran Lleyton Hewitt then secured the tie for Australia Gold with a 7-5, 6-4 win over Jack Sock, and it became a clean sweep for the home side when the mixed doubles was a walkover due to Serena's absence. The result meant the US bowed out of contention in the tournament. But of more concern to its camp was the fitness of the defending Australian Open champion. However, the 21-time Grand Slam singles champion was confident it was only a minor problem and even refused to rule herself out of Thursday's Hopman Cup tie against the Czech Republic. Earlier in the day, Alexandr Dolgopolov put Ukraine within reach of its second Hopman Cup final. In Ukraine's first appearance at the event since being runner-up in 1995, world No. 36 Dolgopolov gave his country two wins from as many ties with his victory over the Czech Republic's Jiri Vesely. After the 19th-ranked Elina Svitolina upset world No. 11 Karolina Pliskova in straight sets in the women's singles, Dolgopolov clinched the tie when he beat Vesely in similar fashion 7-5, 7-6 (7/3). In the dead mixed doubles rubber, the Czechs kept their final hopes alive with a 6-3, 6-1 win. Having already beaten the USA Monday, the result puts Ukraine in pole position to reach Saturday's final. As the only unbeaten team in their group, Dolgopolov and Svitolina simply need to beat Australia Gold in their last round-robin match Thursday to reach the final. Injured Sharapova, Halep out In Brisbane, Australian Open contenders Maria Sharapova and Simona Halep withdrew from the Brisbane International Tuesday after suffering injuries less than two weeks before the first Grand Slam of the year. Romanian top seed Halep was felled by inflammation in her left Achilles, an injury that hampered her 2015 campaign, but was hopeful of being fit in time for next week's event in Sydney. Russian Sharapova, the defending champion, was nursing an arm injury which meant a premature exit and no matches at her only tournament before the Melbourne slam which begins on Jan 18. The world No. 4 had been due to face compatriot Ekaterina Makarova in first round action later on Tuesday but was replaced by another Russian, lucky loser Margarita Gasparyan. That match, on Pat Rafter Arena, was one of several to be delayed Tuesday by rain, causing further headaches for tournament organizers shorn of two of their biggest draw cards. US Open finalist Roberta Vinci became the first woman through to the last eight after the Italian demolished Dominika Cibulkova 6-1, 6-1. In the men's draw, seeds David Goffin and Domini Thiem won Tuesday to make the second round. Venus, Ivanovic fall In Wellington, the top two seeds Venus Williams and Ana Ivanovic were shock first round losers in the WTA Auckland Classic Tuesday. Venus, 35, the tournament top seed and defending champion, was beaten 7-6, 3-6, 3-6 by 18-year-old Russian Daria Kasatkina, while Ivanovic went down in straight sets to British qualifier Naomi Broady 7-5, 6-4. Tournament third-seed Wozniacki moved into the second round with a 6-4, 6-4 win over Montenegro's Kovinic. Francesca Schiavone fell against Austria's Tamira Paszek 7-6, 4-6, 6-3. Kvitova withdraws In China, Petra Kvitova's new year began with a withdrawal from the Shenzhen Open due to illness Tuesday after losing the first set against China's Zheng Saisai. Saisai was leading 6-2 in the first round match when the second-seeded Kvitova withdrew. Top-seeded Agnieszka Radwanska made short work of Serbia's Aleksandra Krunic, winning 6-4, 6-3. She will meet Zhang Shuai in the second round after the wildcard entrant defeated Irina Khromacheva 6-3, 6-3. British No. 1 Johanna Konta also made an early exit, losing 6-3, 3-6, 6-3 to Chinese qualifier Wang Qiang, while Eugenie Bouchard of Canada survived a scare before beating Donna Vekic of Croatia 6-4, 1-6, 7-5.
