MIAMI (AFP) - World number one Rafael Nadal will try to nab a second elite ATP Masters 1000 title in as many starts as he heads the men's field for the Miami hardcourt tennis tournament that starts on Wednesday. Nadal, the Australian Open champion, arrives in Florida fresh from his triumph in the opening Masters event at Indian Wells, California, on Sunday. On the women's side, world number one Serena Williams returns to action after skipping Indian Wells, along with her sister Venus. Nadal, who won his sixth Grand Slam title and his first on hardcourt in Melbourne and said his triumph in California made it a "dream start" to the season, insisted that he couldn't afford to be complacent. "The good thing of tennis is when you lose, you have another chance next week," he said after a lopsided win over Andy Murray in California. "The bad thing is when you win, next Tuesday you are like this another time," he said, clutching his throat with a smile. "It's very difficult to play during all the year your best level." That said, Nadal says he believes he has more weapons at his disposal now. "I think I have more options to do," he said. "I can do more things than before. I can change the rhythm with one sliced backhand. "When I am playing good, I can play more inside than before," he says. "Before, to win every match, I had to run much more than right now. But now I am in control of the point much more than before." That makes him the man to beat in a draw that features 48 of the top 50 players in the world. Nadal's season so far has included his five-set triumph over Roger Federer in the Australian Open final, a runner-up finish in Rotterdam and his win over Scotland's Andy Murray in the Indian Wells final. The 22-year-old has never lifted the trophy in Miami, losing to Federer in the final in 2005 and to Nikolay Davydenko in last year's championship match. Russia's Davydenko won't defend his title because of a lingering foot injury. The field does boast three former champions, 2007 titlist Novak Djokovic, Federer (2005-06) and American Andy Roddick (2004). This year marks the first time since 2003 that Federer doesn't come in as the top seed. The world number two from Switzerland made his return from a six-week layoff at Indian Wells, where he was ousted in the semi-finals by Murray. Federer, a 13-time Grand Slam champion, remains in search of his first title of 2009.Murray arrives in Florida ranked number four in the world, but closing in on world number three Djokovic, who was the defending champion in Indian Wells but fell in the quarter-finals to Roddick. The return to action of the Williams sisters highlights the women's action. Serena is the two-time defending champion, and will be gunning for her sixth title overall in the WTA premier mandatory event. Between them, Serena and Venus have won eight titles in Miami and this year, with Venus seeded fifth, they could meet in the semi-finals. Serena Williams won three straight titles here from 2002-04, and beat Justine Henin in 2007 and Jelena Jankovic in last year's final. In the quarter-finals she could run into sixth-seeded Russian Vera Zvonareva, who triumphed at Indian Wells on Sunday for the first premier-level title of her career. Jankovic, a former world number one whose 2009 struggles continued with a second-round ouster at Indian Wells, could face Venus Williams - winner here in 1998, 1999 and 2001 - in the quarter-finals. World number two Dinara Safina of Russia could face a potentially tricky second round encounter against wild card Sania Mirza of India. Safina, who finished runner-up at the Australian Open, was the top seed in California last week but lost in the quarter-finals, missing out on a chance to overtake Serena Williams atop the world rankings.