Khabib Nurmagomedov believes a rematch with Conor McGregor would "make sense".
But the Russian would only consider the fight if McGregor beats Dustin Poirier at lightweight first.
McGregor, last seen beating Donald Cerrone in January, is said to be close to agreeing a fight with Poirier for next January in 2021.
But the suggestion from his trainer John Kavanagh that the fight could be at welterweight has made Khabib adamant that any rematch would be on his terms.
He told the Mike Swick podcast : "If he beats him (Dustin Poirier) in 155, it makes sense.
"But if they fight in 170, how can you fight in 170 and then next fight be in 155.
"They want to make everything easy. If you want to take it the easy way, you will never deserve another title shot.
"Remember before I fought him, I said 'I am going to make you humble and I am going to put you on the line' and now after two years people understand my words.
"I am going to put him on the line and I am going to make the decision. If he fights 170, bye bye."
But Khabib, who he defeated by submission in October 2018, has also recently doubted if McGregor, 32, has the focus to earn another world title shot.
He told Yahoo Sport : "Conor McGregor, I beat him already. Why (do) I have to fight with him?
"He has to come back and be busy. Tell him be busy and that’s it.
"I don’t think he’s ever going to deserve this title shot because he’s not focused, drinks too much, smashes old people – he don’t deserve my attention.
"Like, coaching with me on Ultimate Fighter or something like this. Forget about him."
