The Indian boxing star, who beat former WBC European champion Kerry Hope to win the title in a gruelling 10-round contest, is unbeaten since turning professional last year, registering seven straight victories, six of which were knock-outs.
He is placed above rising American star Trevor McCumby, who is also undefeated in the circuit with 22 victories, 17 of them knock-outs.
"It's just the start for me; one day I want to be the No. 1 in the world. That's my dream and I am sure I will achieve it," India's first Olympic and World Championships medal winner in boxing said.
A rung above Vijender is US-based Russian Matt Korobov, who has 26 wins in 27 fights.
Jesse Hart of the United States, the reigning North American Boxing Organisation (NABO) champion, holds the No 1 slot.
The Indian could face Commonwealth champion Luke Blackledge in his next fight.
IMAGE: Vijender Singh celebrates after beating Bulgaria's Samet Hyuseinov in the WBO bout in Manchester on December 20, 2015
Photograph: Dave Thompson/Getty Images
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