original question: Which competitor participated in the competitions of [2009 Tour Down Under]?
answer: robbie mcewen, mauro santambrogio, michael rogers...
answer type: Competitor.
auxiliary information: The 2009 Tour Down Under was the 11th edition of the Tour Down Under cycling stage race, taking place over 20 ‚Äì25 January around Adelaide, Australia. The Tour Down Under was the first race outside of Europe to be given ProTour status by the UCI, and this edition was the first race in the inaugural UCI World Ranking calendar. This was the first race in Lance Armstrong's comeback. The race was preceded by an opening race called Down Under Classic, not part of the UCI ProTour competition.
The [2009 Tour Down Under] cycling race is best known for the return of what famous cycling competitor?