In 1991, Khan turned professional. He spent many years struggling to establish his tournament career. His first full season on the
European Tour was 2002 and his first European Tour win came at the 2004
Celtic Manor Wales Open. In 2006 he finished second at the prestigious
BMW Championship to earn €472,220, which was his biggest prize cheque up to that time. His best year-end ranking on the
European Order of Merit has been 25th in 2006 and 2010. He has featured in the top 100 of the
Official World Golf Rankings. After losing his tour card in 2009, Khan was a medalist at the
Qualifying School tournament. In 2010 he won the
BMW PGA Championship, earning €750,000 and securing his Tour card for five years in the process. Khan produced another fine run at the
BMW PGA Championship in 2013, when he recorded the second runner-up finish of his career, to add to his 2010 victory, at Wentworth. After finishing at 10 under par, Khan entered a three-man playoff alongside
Matteo Manassero and
Marc Warren. In the playoff, Warren was eliminated at the first extra hole and after matching pars and birdies, Khan was defeated on the fourth extra hole by Manassero. After a good drive, Khan knocked his second shot into the water and could only make a bogey six and Manassero after two fine shots onto the green, two-putted for the victory. ==Professional wins (5)==