Venus Williams leads US to victory over South Africa

American tennis star Venus Williams gave her comeback hopes a boost with a win at the Hopman Cup in Perth on Sunday, and said she still believed she could be a force in the Grand Slams. The former world number one beat Chanelle Scheepers in three sets to help the United States post a 2-1 win over South Africa in their Group B tie at the mixed teams tournament. Williams, playing for the first time since October and just 24 hours after arriving in Australia, made a slow start against the 60th-ranked Scheepers but steadied to win 4-6, 6-2, 6-3. The seven-time Grand Slam singles winner has climbed the rankings this year as she recovered from a major setback due to illness in 2011. Williams has not won a Grand Slam singles title since her 2008 success at Wimbledon. She slipped to 134th in the rankings last year after suffering from Sjogren\'s Syndrome, a systemic autoimmune disease. However, the 32-year-old has enjoyed much better fortunes this year. She won her first singles title since 2010 in Luxembourg, teamed with sister Serena to win gold in the doubles at the London Olympics and finished the season ranked 24th in the world. Speaking after hitting 44 winners in disposing of Scheepers, Williams said this year was a great platform for the coming 12 months. \"Last year was so awesome for me, winning a tournament and getting to the Olympics and getting a gold,\" she said. \"I was extremely happy last year and moved up quite a few spots. \"This year is just about building on it and continuing to play deep into the draws and put myself in positions to play well deep into the tournaments.\" Williams said she still believed she could be a force in the Grand Slams. \"I always feel that way,\" she said. \"That\'s how you have to feel, you have to be positive. \"I try to be positive and tell myself I\'m the best now. It doesn\'t happen every time but you\'ve got to have that mind frame.\" Kevin Anderson levelled the tie for South Africa with an upset win over fellow big man John Isner in the men\'s singles, the world number 37 beating the world number 14 after two tie-breaks, 7-6 (7/0), 7-6 (7/5). The Americans then prevailed in straight sets in the deciding mixed doubles 6-3, 6-2. In the evening Group A session Spain beat France 2-1, with Jo-Wilfried Tsonga recovering from a break down in the first set to beat Fernando Verdasco 7-5, 6-3 in the men\'s singles, before Anabel Medina Garrigues levelled the tie with an easy win over Mathilde Johansson, 6-3, 6-2. The Spanish dominated the mixed doubles, winning 6-3, 6-3. Meanwhile, Germany\'s Andrea Petkovic has withdrawn from the tournament after injuring her right knee during her singles match on Saturday, and will be replaced in the German team for the remainder of the tournament by Tatjana Malek. The injury-plagued Petkovic, a former top 10 player, has ruptured the meniscus in her right knee and will miss the Australian Open, but hopes to only be sidelined for a month.