Khabib Nurmagomedov has told Kamaru Usman to 'smash' Colby Covington in a good luck message to the welterweight champion ahead of UFC 268.

Usman, 34, faces Covington, 33, at Madison Square Garden on Saturday night, almost two years on from their dramatic five-round clash in Las Vegas that saw Usman win via a late stoppage.

The Nigerian Nightmare has remained the undisputed king since their first fight, with fans and pundits expecting Covington to give Usman his toughest test in the Big Apple this weekend.

Usman and Nurmagomedov are both managed by Ali Abdelaziz and share a friendship, and the Eagle FaceTimed the 170-pound king to implore him to 'smash' loudmouth Covington at UFC 268.

'Really good to see you, brother. Please brother smash this guy [Colby Covington] and defend the belt,' Nurmagomedov told Usman on UFC Embedded.

'My energy with you, brother… Honestly, I really want him to smash this guy like he did the first time. 

'Let's go, Kamaru. Pound-for-pound best in the world. Kamaru Usman, Nigerian Nightmare, African Power. Let's go, brother. I'm with you.'

Usman has taken his game to another level since fighting Covington at UFC 245, winning two of his last three fights by knockout.

He handed Jorge Masvidal his first knockout defeat in over 10 years with a thunderous right hand last April, with new coach Trevor Wittman refining Usman's skills on the feet to add to his world class wrestling and grappling.

Usman believes that he will be far less emotional when he meets Covington this time around, with the American riling the champion ahead of their first fight in 2019.

'For me, the wrong that I want to right is in that fight, I fought with emotion. As much emotion I was willing to display is what I fought with, which is why I think I got hit quite a bit, but it was fun. I had fun,' Usman said.

'That lets you know that I got a little mad man in me too. I don't mind getting hit… I want to make it a little bit more flawless this time around.'