World No 1 Novak Djokovic sounded an ominous, if light-hearted, warning to his Australian Open rivals after suffering a narrow defeat in the Hopman Cup final on Saturday night.

Speaking after he and Ana Ivanovic were beaten by Spaniards Anabel Medina Garrigues and Fernando Verdasco in the mixed teams decider, the defending Australian Open champion was already eyeing his title defense.

"I will have my revenge in Melbourne in a week," Djokovic (pictured) said with a laugh as he exited Perth Arena in the early hours of Sunday morning.