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A pair of title bouts sit atop the marquee along with the return of a fan favorite as UFC 263 invades Gila Arena in Glendale, Arizona, on Saturday in a star-studded pay-per-view card. 

Middleweight champion Israel Adesanya returns from his first pro defeat suffered in a 205-pound title challenge when he welcomes rising contender Marvin Vettori in a rematch of their split decision in 2018. 

Speaking of rematches, flyweight champion Deiveson Figueiredo takes on Brandon Moreno in the co-main event fresh off their five-round thriller in December. The enigmatic Nate Diaz is also back in a rescheduled tilt against welterweight contender Leon Edwards. 

Let's take a closer look at the biggest storylines entering this weekend. 

1. Was Israel Adesanya's hiccup enough to derail momentum? 

It seems almost unfair to judge this closely, especially considering Adesanya, as the defending middleweight champion, attempted such a "dare to be great" endeavor that typically deserves acclaim when he lost a close decision to 205-pound champion Jan Blachowicz in March. But Adesanya's hype, at the time, was simply too large to overlook the potential fallout. Not only was "The Last Stylebender" unbeaten and a betting favorite against Blachowicz, there seemed limitless potential to his ceiling. Had Adesanya won, there was already talk in place of him possibly going directly to heavyweight and continuing his callout of Jon Jones. But Blachowicz used his size, smarts and wrestling to handle him, and now Adesanya returns to 185 pounds to fight a very similar style in Vettori. The much closer betting odds for a typical Adesanya fight suggest this should be anything but an easy task. But what happens should the 31-year-old champion lose his second straight fight, his title belt and a season of rarefied momentum that left many experts wondering if the dynamic striker was unbeatable? Sure, Adesanya talks a great game and always appears cool under pressure, but he brings with him an enormous amount of pressure into Saturday's rematch. 

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2. Marvin Vettori has some sneaky star potential

They say timing is everything in life and that remains no different as it pertains to climbing the political spectrum of UFC's title rankings. With five straight wins since his close loss to Adesanya in their first meeting, Vettori is peaking at the moment and very much deserving of a spot in the overall title picture. But should that have been enough to leapfrog former champion Robert Whittaker in claiming next to face Adesanya, especially given how huge a rematch between those two Oceanic stars could be for Australia and New Zealand? It's an interesting debate. But however Vettori got to this point, it's safe to say he's both a live dog in this title rematch at UFC 263 and the exact type of fighter UFC prefers giving a large push to. The 27-year-old native of Italy fights like an outright savage and talks a pretty good game to back it up, which have both been characteristics that UFC president Dana White has rewarded. Vettori, with his pressure style and strong ground game, also hails from a country and overall region in Europe where UFC has yet to plant its flag in the kind of imprinting way that only a native champion can produce. Add in the fact that White recently revealed how Vettori was a favorite of Lorenzo Fertitta, the former UFC co-owner who still appears to have a large amount of influence over the sport, and it's clear the promotion is willing to give him every chance to succeed. 

3. Saving men's flyweight continues to pay dividends

If it wasn't for an opportunistic Henry Cejudo preserving the long-term health of the 125-pound division by defeating inaugural champion (yet perennially under appreciated) Demetrious Johnson, UFC fans would likely be without such a guaranteed thrill-fest in this weekend's co-main event. The clearing of the deck at flyweight following Cejudo's title vacating and surprise retirement opened the door for a new generation of go-for-broke fighters led by the equally ruthless and exciting Figueiredo. But even though the native of Brazil went on to author a scintillating fighter of the year campaign in 2020 by commandeering the flyweight title and making a splash throughout four appearances, Figueiredo couldn't get completely over the hump last December. After getting docked a point for a low blow in Round 3, Figueiredo was forced to settle for a majority draw against a determined Moreno in a fight that would've been voted as the year's best had it not been for an other worldly Weili Zhang-Joanna Jedrzejczyk fight. Moreno's ability to not take a step back in his pursuit of Figueiredo was synonymous for the division right now and awarded him a rematch. And regardless of who comes out on top, the division appears well stocked moving forward with the likes of Askar Askarov, Alexandre Pantoja, Brandon Royval and Kai Kara France waiting in the wings. 

4. Hard to imagine Leon Edwards having any worse luck

Nearly two years ago, Edwards secured a win over former lightweight champion Rafael dos Anjos, which formally announced him as a future title contender to watch in the 170-pound division. Unfortunately for the 29-year-old native of Jamaica, almost nothing has gone right since then. Edwards signed a new multi-fight deal with UFC in early 2020 but never got a chance to break through to secure a title shot after everything from the pandemic to Khamzat Chimaev's unfortunate health concerns derailed a potential return. Along the way, Edwards was criticized by even UFC brass for his lack of marketing ability. Finally, following a 425-day layoff, Edwards agreed to face Belal Muhammad in March until an accidental eye poke ruled the bout a no contest. Even Edwards' surprise return this weekend against Nate Diaz of all names needed to be rescheduled by another month due to a Diaz injury. Edwards, who hasn't lost since a 2015 decision against current champion Kamaru Usman, likely secures that long-lost title shot deserving of a fighter currently on an eight-fight win streak should he defeat Diaz. The oddsmakers, in fact, believe he will by installing Edwards as nearly a 6-1 betting favorite. But will that be enough to break this current streak of bad luck that also included a backstage assault at the hands of Jorge Masvidal in 2019? Only time will tell inside the Octagon in this rare five-round non-title bout, provided Edwards can actually get there. 

5. Nate Diaz feels like an afterthought

Given how beloved the native of Stockton, California, has become with fans and how underutilized his brand appears to have been by UFC brass (particularly during the three years he took off after a pair of star-making fights against Conor McGregor), it's hard to really come to grips with what Diaz's return really means this time. Unable to get his much preferred high-profile rematches against McGregor or Masvidal, Diaz instead surprised just about everyone by agreeing to fight Edwards. Although the booking can be looked at as a huge risk worth taking since an upset win could make Diaz a darkhorse welterweight title candidate given his star power, Edwards is an opponent who is simply tough to look good against and doesn't bring the requisite fanfare with him to make it worth it. The play appears to be a bit desperate for the 36-year-old Diaz, who wouldn't be himself without making mercurial moves. Diaz has long been prone to inactivity and conflict with UFC management over purses and opponents. While just having Diaz back feels like a good thing for fans, his rescheduling onto UFC 263 somewhat buries his impact on the event hidden behind a pair of title fights. The typical buzz surrounding a Diaz return just doesn't seem to be there this time and a loss, which most are expecting, feels like it could send him further away from ever capitalizing on all of the momentum that was lost by being so inactive after the McGregor fights. Diaz might be back but very few comparatively seem to care. Yes, we are surprised, motherf---ers.