The Bjorn Baker-trained Samadoubt has upstaged a field of weight-for-age stars to win the Winx Stakes at Randwick.

Sent out one of the outsiders in the 10-horse field, Samadoubt led throughout for jockey Tim Clark in the first Group One event of the Australian racing season.

After kicking clear at the 200m, Samadoubt held on to beat evergreen Group One performer Happy Clapper.

Credit: AAP