Oliveira established himself as the No.1 contender to the UFC lightweight title of which he was stripped ahead of UFC 274 for missing weight.
He survived a scare to score a big submission win over Justin Gaethje to extend his winning streak to 11 fights, with 10 of the victories having come by stoppage.
But he's no longer in possession of UFC gold, though he will be competing for the 155lbs belt in his next Octagon appearance.
'GSP' insists the Brazilian needs to be professional and make weight, claiming it's an unfair advantage.
Speaking exclusively to SPORTbible, he said: "You did not make weight and if you don't make weight, it's not fair for your opponent.
"Your opponent has to go through a lot of grind to make weight. It's something that can change the result of the fight.
"You need to be professional and make weight.
"I don't think it's the first time it happened to him but this being said, he's just an incredible fighter."
The former UFC welterweight and middleweight king then singled out Islam Makhachev, saying he's the only fighter who can pose a threat to 'Do Bronx'.
He added: "Who knows maybe he is too big for his own weight class, maybe he needs to go at welterweight. But he's truly the best man right now, the best man in the division and I think there's only one guy that can maybe pose a threat to him now.
"There's a guy Islam Makhachev. Now, the table is set for this fight."
The prospect of facing Makhachev may not tempt Oliveira, who called for a mega showdown against Conor McGregor.
"There's something missing here. The champion has a name and it's Charles 'Do Bronx' Oliveira."
"Hey, Conor McGregor you coming up or are you gonna run away?!"@CharlesDoBronxs :triumph: #UFC274 pic.twitter.com/ZWqAQTKRTi
- UFC on BT Sport (@btsportufc) May 8, 2022
Oliveira vs. McGregor is the 'money fight', according to St-Pierre who continued: "McGregor is the money fight.
"The fight that everybody wants because he's very charismatic and everybody wants to fight McGregor because they know he's going to bring a lot of viewers. So, it's the money fight."
Karate Combat: Season 4 premieres this Saturday night - televised worldwide, visit Karate.com for how to watch in your area.
GSP returns in his Sensei role, joined by UFC standout and fellow karate black belt Stephen 'Wonderboy' Thompson who is also taking a sensei role.
Featured Image Credit: SPORTbible/PA
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