Jan 27 (Reuters) - Dutch cyclist Tom-Jelte Slagter won the overall title at the Tour Down Under on Sunday for his first major victory as Germant sprint ace Andre Greipel claimed the final stage in Adelaide for his 100th career win. Slagter entered the final stage with a 13-second cushion over Spaniard Javier Moreno and all he needed was to stay out of trouble. The Dutch 23-year-old rookie did exactly that over the 90 kilometre city circuit to finish 17 seconds ahead of Moreno.