MELBOURNE: The much-anticipated potential quarter-final between the back-from-retirement Belgians dissolved in 52 minutes today at the Australian Open. That’s the time it took for Kim Clijsters to lose, in embarrassing fashion, her third-round match at the season’s first Grand Slam tournament. The 6-0, 6-1 defeat to Nadia Petrova was the worst of Clijsters’ career and as one-sided as the score indicated. Clijsters lost the first set in just 18 minutes and won only five points in her first seven games. Justine Henin, another Belgian had earlier held up her end of the bargain, with some difficulty, in beating Alisa Kleybanova 3-6, 6-5, 6-2. The two Belgians had been on track to meet in the final eight at Melbourne Park. Defending champion Rafael Nadal advanced to the fourth round on Friday along with Andy Murray, US Open champion Juan Martin del Potro, Andy Roddick and Fernando Gonzalez. Nadal, who beat Roger Federer in last year’s final, beat Philipp Kohlschreiber of Germany 6-4, 6-2, 2-6, 7-5. Nadal broke Kohlschreiber’s serve in the 11th game of the fourth set, then held serve to take the match with a forehand winner. In the fourth round, Nadal will play Ivo Karlovic, who beat Ivan Ljubicic 6-3, 3-6, 6-3, 7-6 (7). Murray, bidding to win his first Grand Slam singles title, beat Florent Serra of France 7-5, 6-1, 6-4 and is one victory away from a potential quarterfinal with Nadal. First, Murray will have to beat American John Isner, winner of the Auckland tournament last week for his first ATP title. The 6-foot-9 Isner continued his strong form by beating 12th-seeded Gael Monfils of France 6-1, 4-6, 7-6 (4), 7-6 (5). No 4 Del Potro beat Florian Mayer of Germany 6-3, 0-6, 6-4, 7-5 and No 7 Roddick advanced 6-7 (4), 6-4, 6-4, 7-6 (3) over Feliciano Lopez of Spain. Next up for del Potro is Marin Cilic, who beat Stanislas Wawrinka 4-6, 6-4, 6-3, 6-3. Gonzalez beat Evgeny Korolev of Kazakhstan 6-7 (5), 6-3, 1-6, 6-3, 6-4. Roddick and Gonzalez will play each other on Sunday in the fourth round, with the American holding an 8-3 edge in career meetings, including a straight-sets win the last time they met in the round of 16 at the 2008 US Open. Henin’s match on Friday was her eighth since she returned from retirement, just long enough to expect better of herself as a seven-time Grand Slam singles champion. She let that show Friday. After fluffing a routine volley to set up two break points for her opponent, she picked up the ball with her racket, bounced it into her left hand and threw it over the net in disgust. The minor temper tantrum seemed to work. Minutes later, a point away from trailing 4-1 in the second set Henin fought back instead to level it. Then she dominated the match. Henin will play Yanina Wickmayer in the fourth round. Wickmayer — who is ranked No 16 but unseeded because she was under a suspension-since overturned-for breaching the World Anti-Doping Agency’s “whereabouts rule” when direct entries closed for the Australian Open — advanced with a 6-1, 6-7 (4), 6-3 win over Sara Errani. Second-seeded Dinara Safina, the 2009 finalist, advanced with a 6-1, 6-2 victory over Britain’s Elena Baltacha. Safina will have a more difficult assignment next round against fellow Russian Maria Kirilenko, who beat Italian Roberta Vinci 7-5, 7-6 (4). Kirilenko also beat 2008 champion Maria Sharapova in the opening round. Former No 1-ranked Jelena Jankovic was upset 6-2, 6-3 by No 31 Alona Bondarenko. Three-time Australian champion Roger Federer, 2008 winner Novak Djokovic, defending women’s champion Serena Williams and her sister, Venus, play third-round matches on Saturday.