Djokovic started his career with Addidas. He broke onto the scene in 2006 and 2007, winning Masters Series titles, and reaching the latter stages of Grand Slam tournaments, most notably reaching the finals of the US Open in 2007. Djokovic put up a strong fight, announcing himself to the 15,000 capacity crowd inside the Arthur Ashe stadium, but ultimately succumbed in straight sets to Roger Federer, who was in the prime of his career
Just four months later at the Australian Open however, Djokovic got his revenge, defeating Federer in straight sets to reach his second Grand Slam final. There he met Frenchman Jo-Wilfried Tsonga, who he outlasted in four sets. It would be the first of many Grand Slams, and the first of 9 at the Australian Open, an Open Era Record.
Many expected Djokovic to kick on and win more slams, but he wasn't able to add to his tally in 2008, and failed to reach a slam final in 2009. His fitness was a huge concern around this time, and he gained a reputation for quitting when the going got tough, retiring most notably in the quarter-finals of the Australian Open in 2009 against Andy Roddick
