Aldo being challenged in a way he never had (and rising to it). The visible improvements Mendes made from their initial meeting in 2012. The action, of course, including each fighter scoring a knockdown in the first round. The animosity leading up to the fight, but then the level of respect shown during it. The brilliant Rio de Janeiro atmosphere, complete with a pink-shirt-wearing Conor McGregor looming in the background.
"I feel like I poured my heart and soul into that fight," Mendes told ESPN.com. "There is something to be said about two guys getting inside the Octagon and beating the crap out of each other for 25 minutes straight. I gave him a hug after the fight.
"It's just crazy -- we're opponents, we literally know nothing about each other's real lives, we're just athletes competing -- but when two guys have a fight like that you almost get some sort of weird bond. It's a mad respect for each other, I guess. You can see that in our fight."
There were plenty of reasons, both in the buildup to the fight and during it, for Aldo and Mendes to feel animosity toward one another. Aldo knocked Mendes down with a right hand well after the bell after the first round. Mendes poked Aldo in the eye in the first and third rounds. He accidentally kicked him in the groin in the second.
After each infraction, however, the fighters touched gloves and nodded, eager to get back to the technical aspects. In the third round, after a sequence in which each featherweight appeared to get hurt, Mendes spoke casually to Aldo as they were tied up on the fence. The Brazilian smiled and said something back.
It was the kind of fight that elevated both participants, despite the fact that one had to lose. Mendes pushed Aldo in ways we had never seen before, but Aldo once again cemented his spot at the top of the 145-pound division by winning four of the five rounds.
Every time Mendes appeared to turn the tide in his favor, Aldo roared back.
"It almost felt like desperation at times from him, where he'd get popped and start swinging back like he had to make it up right away," Mendes said. "But that's just a champion's mindset. He's been a champion for a long time because he has that."
According to Fightmetric, Aldo landed a career-best 102 total strikes at UFC 179. He was also hit 77 times, the most of any fight in his career.
"The night of the fight, when I got back to my room, I had to just prop my feet up and I actually took an ice bath there at the hotel," Mendes said. "I didn't really sleep at all that night. There was so much swelling in my shins. It was pure pain all night, honestly.
"It was an honor to be in that kind of fight. It's something I'll be able to share with my grandkids. I'm actually excited to get a third fight going between us."