Former world champion Jeff Horn would like to see countryman George Kambosos activate his rematch clause for an immediate second encounter with Devin Haney. 

Last Sunday at Marvel Stadium in Melbourne, Haney outboxed Kambosos over twelve rounds to become the undisputed lightweight world champion by unifying the WBO, WBC, IBF, WBA titles.

After the fight, Kambosos vowed to exercise his right to an immediate rematch.

"Yes, 100 per cent we will do it again,' Kambosos said. "If I hadn't given him this shot, he wouldn't have had his moment right now. Today they gave him the decision, but I'm sure it will change when we get it on again."

Horn believes Kambosos can change things around in a second encounter.

"I think George should take the rematch," Horn said via The Herald Sun. "I definitely showed against [Michael] Zerafa you can come back and win a rematch and I did it after being stopped in our first fight.

"George can definitely upset Haney in a rematch, but he has to knuckle down and change his entire game plan to have any hope of beating him. As a fighter, you want to avenge a loss and I have no doubt George will want another shot at Haney later in the year."

Ironically, Horn shocked Kambosos' good friend and mentor, Manny Pacquiao, in one of the biggest sporting events on Australian soil.

He says Kambosos must implement some of the same tactics that he used to shock the Filipino star.

"George has to do what I did to Pacquiao where I got in his face. Kambosos has to upset his range. He stood too much in the mid-range and that enabled Haney to just jab him. That set the whole fight up for Haney to comfortably win a points decision and George didn't do much during the fight to shake things up," Horn said.

"It was a dominant performance from Haney. George tried hard but he didn't have the right strategy to beat Haney at his game. Haney has a brilliant jab and that just controlled the fight."