By Nick Mulvenney SYDNEY (Reuters) - World number one Jordan Spieth returns to the course where he rediscovered the art of winning last year to defend the Australian Open title he clinched with a quite brilliant final round. The American arrived in Sydney last November ranked 14th in the world with just one U.S. PGA title to his name but shot a course record 63 to beat Rory McIlroy and Adam Scott, then the top two in the world, and secure the Stonehaven Cup. "I didn't think it would launch that type of year," Spieth told reporters at The Australian Golf Club on Tuesday. More...