A lightweight unification fight between Conor McGregor and Tony Ferguson has gained more ground after the Irishman's coach John Kavanagh labelled it as "the fight that makes sense".

Ferguson became interim lightweight champion after submitting Kevin Lee in the third round of their UFC 216 main event in October.

Ideally, "El Cucuy" is expected to face McGregor next to unify the titles. However, the "Notorious" has been rumoured for a variety of different match-ups including a possible super fight with Georges St-Pierre as well as a trilogy bout with Nate Diaz.

With many in the combat world preferring for the lightweight champion to defend his belt, there was hope for Ferguson as McGregor revealed that he planned on legitimizing the belt and the rankings.

"I feel to legitimize the belt — there's an interim champion, I'm the unified champion — I feel that will be next," McGregor said. "We are currently in contract negotiations, and we'll see where it goes."

There is even more hope now after head coach Kavanagh revealed how he believes a fight with Ferguson makes more sense than a potential fight with St-Pierre.

"To me, that fight [McGregor vs GSP] makes no sense," Kavanagh told MMAFighting. "He's fighting at 185. He was a big 170er, but to me athletically it doesn't make any sense."

"Tony Ferguson is the fight that makes sense at lightweight. I think that lightweight is Conor's ideal weight class, so Tony is the fight that seems right at the moment."

There has been a lot of discussion and debate on whether McGregor will defend against Ferguson as while the latter is arguably the most dangerous opponent for the 29-year-old, he is not regarded as a draw compared to "GSP" or Diaz.

But Kavanagh feels as long as any opponent is facing McGregor, the fight will sell.

"It doesn't really matter how much Tony draws or doesn't draw, look at the guy he's facing," he explained. "You could put Conor in there against anyone at the moment and people are going to want to watch it."

"Obviously, GSP is a huge name and he would draw really well, but this weekend [UFC 217] might not go his way and that might be a mark against his selling power.

"Regardless of the opponent, I think Conor versus anyone is the biggest fight of all time. It's all about Conor, he is the sport's biggest star and the biggest pay-per-view draw at the minute."