Conor McGregor believes the public drastically underrates his cardiovascular fitness.

Endurance has long been considered one of the former UFC champion's biggest weaknesses. McGregor appeared to tire out in his first fight with Nate Diaz in 2016, which ended in a second-round submission defeat, and he again started to fade toward the end of the rematch five months later.

But the Irishman believes extraordinary circumstances negatively affected his performance in the first Diaz clash. Beyond that, the 32-year-old hasn't had many chances to prove his cardio is better than perceived, as most of his UFC wins are early finishes.

"I think it's a myth," McGregor said Thursday at the UFC 257 press conference when asked about the doubts surrounding his endurance. "Obviously, I had the first Diaz fight, I went from featherweight and then a month or so later I was at welterweight. That's obviously going to have an impact, and then there were other issues.

"But I think overall it's a myth. ... I hope we can answer it," he added. "And I will answer it in time, at some stage. I keep showing up here. Someone's going to be able to stay in the pocket with me and stay in there and fight with me."

McGregor is scheduled to return from a one-year layoff against Dustin Poirier in UFC 257's main event, which takes place Saturday in Abu Dhabi, United Arab Emirates.