Former boxing World Champion Jeff Fenech believes Australian Jeff Horn has the weapons needed for a shock upset over Manny Pacquiao.

While the fight has yet to be finalised with negotiatons continuing about the location and final purse, the Australian seems certain to take on boxing great Pacquiao on April 23.

Fenech, the winner of world titles in three weight divisions, says if Horn can get inside the Phillipino champions defence and take away his space, then an upset is a definite possibility.