The 30-year-old is embarking on his comeback after nearly two years out of the octagon and faces the man who supplanted him in the division.

Nurmagomedov collected the vacant title with a lacklustre points win over late replacement Al Iaquinta in April and Pettis pointed to that display as one of the reasons he is tipping McGregor for victory at UFC 229.

While Pettis rates Nurmagomedov as the current best in the weight category, he said at the UFC's Performance Institute in Las Vegas: "I think Conor wins by knockout.

"We saw (Nurmagomedov's) last fight against Al and we saw how he performed. If he comes like that against Conor, it's the wrong guy to do that against. I'm sure he's motivated, I'm sure Conor's motivated but I'm picking Conor.

"I think Conor's win over Eddie solidifies him more as a champion than Khabib beating Al Iaquinta, that's just facts.

"The belt is where it is, they had to do it for the business and move it forward but if it was true to the game then Conor would be the champion."

Pettis has been beaten five times in his last eight fights but could put himself back in the lightweight mix with victory over the number two-ranked Tony Ferguson in the co-feature at the T-Mobile Arena.

The American said: "I'm fighting Tony Ferguson. A guy like that made me wake up motivated every day. It felt good to get up motivated. I got this guy in front of me and he's a killer and I'm a killer so it's a kill or be killed.

"I think my performance will send a message. I come to fight and he comes to fight so it's a great recipe for a great fight."

However, the 31-year-old, who reigned supreme at lightweight from August 2013 to March 2015, is not counting on an immediate shot at the winner of Nurmagomedov-McGregor if he dispatches Ferguson.

He added: "Who knows? I feel like it's not about the rankings any more, it's about popularity. If I go out there and pull out the 'Showtime Kick' then I'm getting a title shot. It all depends on who the fans want to see fight."

PA