SYDNEY (AFP) - World No. 6 Karolina Pliskova has withdrawn from the Sydney International with a left thigh injury, tournament organisers said on Sunday.

The Czech, the fourth seed for the Sydney event, demolished France's Alize Cornet 6-0, 6-3 to win the Brisbane International on Saturday.

As her withdrawal came before the start of the first match, Italian Roberta Vinci - as the next eligible seed - took Pliskova's open spot and a qualifier/lucky loser would come into the draw, organisers said.

Pliskova is set to leapfrog Dominika Cibulkova to become world No. 5 when the new rankings are released on Monday.

Pliskova is one of the favourites for the Australian Open, which begins in Melbourne next week. She was runner-up to world No. 1 Angelique Kerber at last year's US Open.