Novak Djokovic made a dazzling start to his Australian Open defence Tuesday but his close rival Andy Murray was slower off the blocks and home hope Samantha Stosur became the first big name to fall. World number one Djokovic powered past Italian Paolo Lorenzi 6-2, 6-0, 6-0, in a comprehensive victory in which he even won a point with an audacious trick shot between his legs. By contrast Murray, runner-up to the Serb last year, was embarrassed by a near-identical party-piece from Ryan Harrison before subduing the American 4-6, 6-3, 6-4, 6-2. Injury-plagued Australian veteran Lleyton Hewitt ground out a trademark late-night, four-hour marathon 7-5, 6-4, 3-6, 7-5 win against 83rd-ranked German Cedrik-Marcel Stebe to set up a second-round match with Andy Roddick. Five-time women\'s champion Serena Williams dispatched Austria\'s Tamira Paszek in straight sets 6-3, 6-2 but was not off the court until nearly 1:00 am, as the match only began at 11:30 pm following Hewitt\'s win. But Australia\'s US Open champion Stosur became a major casualty as she froze in front of her home fans, allowing Romania\'s Sorana Cirstea to record a famous straight-sets victory. Wimbledon champion Petra Kvitova and glamorous Russian Maria Sharapova, the 2008 Open winner, both started strongly and 2008 runner-up Jo-Wilfried Tsonga went through alongside fellow French seeds Gael Monfils and Richard Gasquet. However, Djokovic looked the pick of the men\'s players as the Wimbledon and US Open champion launched his pursuit of a third straight grand slam title in style, exemplified by his crowd-pleasing trick shot. Leading 3-0 in the third and standing on the baseline, Djokovic turned his back to the court and clipped a shot between his legs to the flummoxed Lorenzi, who embarrassingly netted. It was a sign of overflowing self-belief in the Serb, who won 10 of 11 finals and went 70-6 last year -- despite being derailed by injuries after the US Open -- in a season described by some as the best in tennis history. \"I just have more confidence that I\'m playing on right now. I just believe that I can win, especially against the biggest rivals in the major events,\" Djokovic said. Later Murray, seeking Britain\'s first male grand slam title since 1936, became the first top-four man to concede a set before gaining the measure of Harrison -- apart from the American\'s trick shot while trailing in the fourth. \"Today was a bit of a shock to the system,\" said Murray, referring to the hot afternoon weather. \"It was good to get used to playing in that heat again because I might have to a bit further down the line.\" Stosur, who has only won one match in three tournaments this year, all in Australia, put in an error-strewn performance as she became the latest women\'s grand slam champion to fail in her very next major. \"There\'s not any other word for it but a total disappointment,\" she said. \"It\'s not through lack of trying or not wanting it or anything like that. I mean, you can\'t pick the times that you want to play well,\" Stosur added. \"Of course, I wanted to do very well here. You want it to come right now. I\'m thankful that everyone was behind me. I\'m sure they will stay behind me.\" Meanwhile, second seed Kvitova and Sharapova, the world number four, made convincing starts at sun-drenched Melbourne Park. As temperatures again climbed past 30 degrees Celsius (86 degrees Fahrenheit), Kvitova raced past Russia\'s Vera Dushevina 6-2, 6-0 and Sharapova pummelled Argentina\'s Gisela Dulko 6-0, 6-1 in less than an hour. \"I knew I had a tough opponent today,\" a delighted Sharapova said afterwards. \"I focused on every point and took her time away -- she\'s a player who loves time on the ball.\" Estonia\'s Kaia Kanepi, who won the Brisbane tournament, beat Sweden\'s Johanna Larsson 6-2, 6-4 to reach the second round. Japan\'s Kei Nishikori came through in three sets against Stephane Robert of France and bullet-serving Canadian Milos Raonic, a winner this month in Chennai, eclipsed Italy\'s Filippo Volandri for the loss of just six games. Spanish fifth seed David Ferrer beat Portugal\'s Rui Machado in straight sets, and Serbia\'s Viktor Troicki came through in five against former French Open champion Juan-Carlos Ferrero.