He became the youngest player to ever compete in the junior division of the Australian Open, when he gained direct acceptance in 2007 at age 14. He went on to win two Junior Grand Slam titles, one at the Australian Open, and another at the US Open. He began competing in professional tournaments in 2008, when he was 15, even though he was still eligible for junior competition. He achieved his greatest success in professional Grand Slam play so far, at Wimbledon in 2011, when he reached the quarterfinals.