By Matt Smith DUBAI, Nov 12 (Reuters) - Legal problems were a distraction which affected his golf this year, former world number one Rory McIlroy said on Tuesday as he prepared to defend the World Tour Championship title he won in sizzling style last year. The 24-year-old from Northern Ireland birdied the final five holes in Dubai 12 months ago to claim his second tour title of the year and finish top of both the European and U.S. money lists. That slump followed McIlroy's sponsorship switch to Nike in January, which prompted a former sponsor, American sportswear company Oakley, to launch legal action against him. In September he terminated his contract with Dublin-based Horizon Sports Management to form his own management company and the acrimonious split has now reached the courts. More...