'I was making a lot more errors. She did play very well at the right time' Fighting fit Venus Williams experienced a roller-coaster ride as she began her title defence at the Watsons Water Champions Challenge in topsy-turvy style at Victoria Park last night. Despite having her left thigh heavily strapped as a precautionary measure, the 24-year-old American proved too strong for Russia's Vera Zvonareva, winning 6-2, 4-6, 7-5 to show that she wasn't about to surrender her Hong Kong title without a fight. Wearing a T-back black top which bared her muscular shoulders, the four-time Grand Slam winner blasted her way past the 20-year-old world number 11 in a quick-fire opening set. But she had to endure frustration brought on by erratic play in the second before finally killing off the hopes of her younger rival. Williams, a two-time Wimbledon champion, was sharpening her skills for a much bigger test ahead in the shape of US Open champion Svetlana Kuznetsova in tonight's mouth-watering Green Group clash - a match that will determine who plays in tomorrow's final. Williams certainly looked shaky at times, although she showed no sign of the injuries that blighted her season last year. Her movement flowed despite her heavily strapped thigh and the power in her serves and returns was back to normal. Zvonareva - a Russian on the fringe of entering the world's top 10 - is no slouch and she blew a golden opportunity to claim a famous scalp after leading 5-3 in the deciding set. But nerves got the better of the Russian as she eventually succumbed to the American, who displayed all the power, quickness and artistry needed to win the power-hitting contest. 'I think it was an up and down match as far as the amount of errors. When I was down I was making a lot more errors. She did play very well at the right time,' said Williams after the match. Williams was upbeat about her clash with big-serving Kuznetsova, saying she had played the Russian several times before. 'I feel very good. I've played Svetlana a few times and she has a similar game to mine,' Williams said. 'But I definitely feel like playing very well.' She added: 'The crowd was really good. I felt they were really behind me but also at a lot of times, they were behind Vera as well. So they were very fair and I appreciate that.' Asked whether she was tired after the match, which lasted almost two hours, Williams replied: 'I am too young to be tired.' Williams started off well, taking a 4-1 lead in the first set as she pounded her groundstrokes, winning numerous rallies including a tremendous cross-court volley that won her the seventh game to lead 5-2. She ripped a forehand down the line to snatch the opening set as Zvonareva watched helplessly when the ball plopped inches inside the baseline. But fans expecting an easy win for Williams were given a surprise as Zvonareva raised her game a notch as the American made a series of unforced errors after suffering a lapse of concentration for the Russian to win a tight second set. The American stepped up the pressure in the third set as she took a 3-0 lead only for the resilient Russian to stage another fightback, reeling off five straight games to lead 5-3. Williams held serve at 4-5 and tied the set at 5-5 thanks to a lucky cord break when a forehand return hit the strap of the net before dribbling over on to Zvonareva's side of the court. It was the beginning of the end for the Russian and Williams regained her composure to win the next two games with Zvonareva double faulting at the most crucial time, allowing Williams to finally score a hard-fought win that kept her title hopes alive. Meanwhile, rising Czech Republic star Nicole Vaidisova withdrew from the tournament, citing illness - giving Russia's Elena Dementieva a clear passage through to tomorrow's final. The 15-year-old Vaidisova, who was supposed to play Dementieva in last night's second singles, was upset that she had to withdraw from the tournament. A tearful Vaidisova said: 'I am very, very disappointed. This was such a good opportunity to compete against so many top players, but sadly I just cannot make it.' Tournament co-director Terry Catton said: 'In these circumstances, Elena Dementieva receives a walkover. The tournament apologises to the fans, but it's a situation we cannot control.' In the doubles competition, Venus and sister Serena reached tomorrow's final without playing a point after receiving a walkover from Dementieva and Vaidisova. They will play Kuznetsova and Arantxa Sanchez-Vicario of Spain for the title. Spectators were treated to an exhibition match with Dementieva and Zvonareva taking on the Williams sisters last night. The Russians won 7-5, 7-5.