Robert Whittaker believes Yoel Romero was his toughest opponent at middleweight.

At UFC 225, middleweight champion Robert Whittaker took on Yoel Romero. The bout was a non-title five-round headliner. Romero missed weight, which is why Whittaker’s title wasn’t at stake.

“The Reaper” ended up taking a narrow split decision victory. Whittaker was knocked down in the fight and looked to be in danger of having the bout stopped. Nonetheless, the champion showed heart and grit to eek out the win.

Speaking to The Daily Telegraph, Whittaker said Romero felt unique to any previous opponent:

“I know you probably agree he doesn’t look like a middleweight and I can tell you he doesn’t feel like one either. Except for my face, all the damage on my body is from me hitting him. This time, he felt like steel. I was punching and kicking him but it wasn’t doing any damage. He was walking forward through everything. It was weird. My shots just weren’t stopping him. I’ve fought everyone in the middleweight division — including Romero previously — and I’ve never seen anything like that.”

Whittaker and Romero fought once before UFC 225. Back in July 2017, Whittaker took a unanimous decision win over Romero. While that fight was close as well, “The Solider of God” never came close to finishing the fight as he did in the rematch.

While the rematch was an instant classic and the result was close enough to usually warrant a third bout, Romero’s weight cutting issues may force him to move up to light heavyweight. If there ever is a third bout between Whittaker and Romero, it isn’t likely to happen anytime soon.