MADRID (AFP) World number one tennis ace Rafael Nadal Wednesday downplayed his achievement in completing a career Grand Slam, describing it as merely a step forward in his career. Im not the best sportsman, its quite obvious that Im not, the Spaniard told a news conference on his arrival at Madrids airport from New York. Nadal on Monday became only the seventh man in history and the youngest at 24 to have won the worlds four top tennis tournaments: the US, French and Australian Opens and Wimbledon. The left-hander achieved the feat after he overcame second-ranked Novak Djokovic 6-4, 5-7, 6-4, 6-2 at Flushing Meadows to capture his first US Open crown. As a tennis player I have taken a step forward, he said of the achievement, adding that he maintains the hunger for victory and the hope to keep winning. But he described the Grand Slam as a dream as the US Open has been in past the one that has been hardest for me. First of all there was my knees, he said, referring to the tendinitis he suffered the 2007 edition, when he lost in the fourth round to David Ferrer. The following year, I was very tired after the Olympics, and last year I pulled an abdominal muscle. Nadal said the 2010 season so far has been very special, as when you dont win for some time and then you start winning again it means that you have overcome the problems. He said he was now focused on the Shanghai tournament and the Masters events in Paris and London. Nadals win adds to a list of successes for Spanish sportsmen this year following the countrys first ever World Cup win in South Africa and Alberto Contadors third victory in the Tour de France.