One thing we didn't learn last weekend: 2016 is the Year of the Underdog.

That much we already knew. There has never been this kind of turnover in UFC title fight history -- considering not only the frequency of belts switching hands, but the manner in which they are doing so.

Stipe Miocic: First round. Eddie Alvarez: First round. Amanda Nunes: First round. Michael Bisping: First round. And now added to the list, Tyron Woodley: First round.

"Anything can happen in MMA" and all that jazz, but this has gotten out of control.

But again, we already knew that going into UFC 201. Here's what we didn't know, and thus What We Learned, over the weekend in Atlanta.

It's good to be a Diaz

Brothers Nate and Nick Diaz are getting big fights. David Dermer/Diamond Images/Getty Images

I like to picture Nick Diaz on a boat off the coasts of Mexico last Saturday, toasting shots with brother Nate Diaz, UFC 201 welterweight championship softly playing in the background -- no one giving it any thought.

The Diaz brothers have reached, at least for the time being, what actually might be the pinnacle of MMA. That is, big fights come to them. They're not chasing anything. Neither holds a belt, but the champions who do are calling them out.

Shortly after Woodley demolished Robbie Lawler at UFC 201, he was interviewed on live television by Stephen Thompson, the next obvious No. 1 contender. A very polite, very deserving Thompson essentially asked Woodley if he was ready to dance with him next. Woodley stared coldly into the camera and shut poor Thompson down.

Could GSP return to challenge Woodley? Chael Sonnen says that former UFC welterweight champion Georges St-Pierre could return from retirement to challenge Tyron Woodley for the belt. Watch

Woodley wants a "money fight" against Nick Diaz or former champ Georges St-Pierre. Thompson is nowhere on his radar. And as crazy as it sounds, Diaz jumping the welterweight line doesn't sound that far-fetched.

Heck, he's done it before. He fought St-Pierre for the title in 2013, despite coming off a loss. He's officially 0-2 in hist last two fights, with one no-contest thanks to a failed drug test by Anderson Silva last year. He just served an 18-month suspension for his own failed drug test (marijuana). His only win in the UFC within the last nine years is a decision against a hopelessly undersized B.J. Penn five years ago.

Thompson, meanwhile, is on a seven-fight win streak. This year alone, he's knocked out Johny Hendricks in the first round and prevailed over Rory MacDonald in a five-round fight.

Diaz has no business fighting for a title before Thompson, but if that's the route the UFC goes, it won't be that surprising. Nate, meanwhile, is currently the only man Conor McGregor is willing to fight -- and lightweight champion Eddie Alvarez is also on-record wanting a fight against him.

Regardless of how you feel about it, there's no doubt: "Diaz" business is booming.

Joanna Jedrzejczyk gonna hold that strawweight title for a minute

Strawweight champion Joanna Jedrzejczyk is unbeaten in her MMA career and has a 6-0 record in the UFC. Al Powers for ESPN

No one is safe. We must constantly remind ourselves of this. But if there is a fine print to this rule, it most certainly reads, "Oh, wait, except for Jedrzejczyk."

Kowalkiewicz beats Namajunas via split decision Karolina Kowalkiewicz survives Rose Namajunas with a split decision victory. Watch

Rose Namajunas was being touted as one final potential hiccup to Jedrzejczyk's title reign. Even before her loss to Karolina Kowalkiewicz on Saturday, there was reason to believe Namajunas wasn't quite ready. Now, there's no doubt that's the case.

Kowalkiewicz (10-0) is undefeated, tough and in good shape. She accused Jedrzejczyk of being "scared" of her at the UFC 201 post-fight press conference, a claim that seems ... unconvincing. An all-Poland title fight sounds like a good time, especially if the UFC can land it in the country's capital of Warsaw. But even in a time when champions are falling like flies, I'd set the odds of Jedrzejczyk being one of them close to zero.