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Kamaru Usman and Rose Namajunas passed big tests at UFC 268 on Saturday night, retaining their status as champions in rematches against talented rivals. Now, having defeated Colby Covington and Weili Zhang, respectively, both champions leave Madison Square Garden in New York City knowing that more stiff tests for their championships await.

The two title fights headlined an incredible card that saw a run of seven consecutive knockout finishes, an all-time great fight and a legend coming up short in a spirited effort. It was the kind of night every UFC fan hopes for when they plop down their hard-earned money for a pay-per-view.

There are plenty of things to take away from such a massive show. Let's take a look at four of the biggest storylines coming out of UFC 268.

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Kamaru Usman gets the job done -- barely

It wasn't always pretty for Usman in his welterweight title defense against Covington, but he did what the best fighters in the world do: he won. Usman appeared to be cruising to a short night when he scored two crushing knockdowns of Covington late in the second round. A combination of Usman's respect for Covington and Covington's undeniable toughness led to a tough final three rounds, with Covington winning Round 3, 4 and 5 each on at least one official scorecard.

That all adds up to a very close call for Usman, who was not only seeking to continue his dominant run as welterweight champion, but also continue making his case as the greatest welterweight in UFC history. Usman isn't quite the best welterweight UFC has ever seen, that's an honor still very much held by Georges St-Pierre, but winning tough fights are a part of building a legacy.

It's also clear that Covington may just be the toughest test available for Usman. Having dispatched of Covington twice now, and with the men hugging and expressing mutual respect after the fight, there's no steam left in the rivalry and Usman can move on to the next rivalry. It's now on Usman to build his resume while defending his status as champion and the UFC's top pound-for-pound fighter.

Justin Gaethje and Michael Chandler delivered greatness

There have been plenty of fights in UFC history given the "can't miss" label only to disappoint in one way or the other. That was not the case when Chandler and Gaethje went to war to kick off the UFC 268 main card. The expectation was that the two heavy-hitting lightweights would throw bombs until one man fell in a fight that would win Fight of the Night. All of that happened, except neither man stayed down and instead of Fight of the Night, Gaethje and Chandler put on arguably the Fight of the Year -- and a fight that will go down as one of the best in the history of the Octagon.

Neither man has anything to feel bad about after this fight. Chandler had Gaethje badly rocked in the first round, and Gaethje dropped Chandler with a perfect uppercut in the second. Still, somehow neither man backed down. Gaethje deserved the win and now is in position to fight the winner of lightweight champion Charles Oliveira and Dustin Poirier for the belt. But both men proved they are among the elite in the world both in skill and heart.

'Thug' Rose proved her second title win was not a fluke

One downside of a title win that comes in less than two minutes is that some fans and media will write your victory off as a fluke. When Namajunas landed a head kick and a few follow-up punches to score a quick TKO over Zhang in April, becoming a two-time women's strawweight champion in the process, her victory was lumped by some into that "lucky shot" category. On Saturday night, the two women rematched and victory would not come so quickly -- or easily -- for Namajunas the second time around.

Namajunas got off to a slow start in the rematch, with Zhang landing leg kicks and even utilizing some wrestling to make things much harder on the champion. Namajunas made every necessary adjustment throughout the fight, keeping a distance that better allowed her to utilize her reach and realizing she could score with her own takedowns to dominate the championship rounds with her top game. While the old adage that "you're not a true champion until you've defended your title" is nonsense, Namajunas erased any doubts as to her true place in the strawweight division by having to go through the fire in the rematch with Zhang.

The sun is setting on Frankie Edgar's career

Edgar is in a tough spot. The former lightweight champion has dropped to featherweight and now bantamweight in pursuit of another championship run. In every division, he has been undersized and was positively dwarfed by Marlon Vera on Saturday night. Where Edgar's chin and speed have been great tools through his career, they just aren't cutting it anymore.

Edgar showed off his wrestling at the start of the fight with Vera, but the size and pace wore on him as the fight went on and Vera was eventually able to land several damaging shots before a front kick to the face sent Edgar to the mat and ran his bantamweight record to 1-3. Edgar is good enough that he can beat some men in the lower end of 135 pounds, but is that enough for one of the UFC's all-time greats? There's nothing for him at featherweight or lightweight and time is catching up to him at 40 years old. It's unfortunate that the end comes for everyone, even the greats. Edgar has to be wondering how much more he has in the tank, especially if a championship seems well out of reach.