At UFC 249, Justin Gaethje will step into the Octagon to face off with Tony Ferguson for the interim lightweight championship. The fight is happening under a number of odd circumstances. The fight will take place in an empty arena due to the ongoing coronavirus pandemic and with Gaethje stepping in on short notice after Ferguson's fight with lightweight champion Khabib Nurmagomedov fell apart. The champ returned to his home country of Russia last month as uncertainty swirled over the status of the event, originally scheduled for April 18 in Brooklyn and moved to an undisclosed location -- which turned out to be Tachi Palace Casino Resort in California. Gaethje stepped up for that date before the event was ultimately postponed to May 9 at VyStar Veterans Memorial Arena in Jacksonville, Florida.

Even with the delay, Gaethje is still taking the fight on what amounts to short notice, accepting the bout on April 6, slightly more than a month out from what turned out to be the official date of the card. Topping it all off, gathering restrictions due to the pandemic have left training options slim.

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Gaethje is hardly the first man to step into the Octagon on short notice for a fight in which he is expected to come up on the short end of the result. But there are plenty of fights to look back at that prove stepping in on short notice can provide huge rewards.

Let's take a look back at three iconic times a fighter took the risk and came out with a win.

Nate Diaz def. Conor McGregor -- UFC 196

Few fights in UFC history have had everything come together so perfectly with as shocking a result as the first fight between Nate Diaz and Conor McGregor. On just 11 days notice, Diaz stepped in after an injury to Rafael dos Anjos derailed McGregor's plans to challenge for the lightweight title. After Jose Aldo and Frankie Edgar were ruled out as replacements, Diaz was called in to face McGregor in a welterweight fight. While UFC president Dana White told fans Diaz was training for a triathlon, Diaz would later reveal that he was "on a yacht in Cabo getting my chillax on with my dude Gilbert Melendez."

After a series of press conferences with both men delivering great quotes, the two stepped into the cage on March 5, 2016. McGregor unloaded in Round 1, blasting Diaz with left hands and kicks and cutting the Stockton, California native. Diaz came roaring back in Round 2, landing his own left hand repeatedly as McGregor wore down from his high output in the opening frame. Eventually, Diaz locked in the fight-ending rear-naked choke, shattering McGregor's aura of invincibility and becoming a superstar in the process before delivering his iconic post-fight quote. "I'm not surprised, motherf---er."

Michael Bisping def. Luke Rockhold -- UFC 199

In November 2014, Luke Rockhold submitted Michael Bisping in a Fight Night main event. It was yet another stumble against "elite" middleweight competition for Bisping, who had built a great career while never quite breaking through to title contender status. Twice, Bisping lost title eliminators and had a title shot slip from his grasp. After the first Rockhold fight, Bisping rattled off three consecutive wins when things broke his way. Chris Weidman suffered an injury and had to pull out of a fight with Rockhold, who was now middleweight champion. Bisping got the call for a rematch on 17 days notice and his first shot at a title in his 26th UFC bout.

Ahead of the fight, Bisping told Sirius XM, "Listen, I'll put it like this. If people can walk around -- and I don't mean this in a disrespectful way to religious people -- and you believe the son of God came down to earth 2,000 years ago, and he killed himself for our sins, and he can walk on water, and there's a God up there looking after ourselves, and if you get on your knees and pray to him that things will change, if you can believe that, then you can believe that I can knock the f--k out of Luke Rockhold two weeks from Saturday." He would do just that, taking less than one round to finish Rockhold and win the middleweight championship in a shocking upset.

Chris Leben def. Yoshihiro Akiyama -- UFC 116

Yoshihiro Akiyama entered UFC 116 on a 12-fight winning streak and had lined up a huge fight with legendary Brazilian mauler Wanderlei Silva. Silva, however, broke his ribs in training and Chris Leben got the call. Leben was a standout on the first season of "The Ultimate Fighter", coming across as a mentally unstable brawler who was always down to go to war. Leben had battled his way to a title eliminator with Anderson Silva at one point but was crushed by the legend in his UFC debut. That kicked off a 5-5 stretch for Leben before he got the call to face Akiyama, something Akiyama took exception to, claiming he wanted a higher caliber opponent than "The Crippler."

Leben took the comments personally, especially given he took the fight on less than two weeks notice and mere weeks after beating Aaron Simpson. "For him to say that I'm not a worthy opponent kind of throws me off," Leben said. "I've got 10 wins in the UFC. He's got one win by split decision over Alan Belcher. I don't think that qualifies him as saying I'm not a worthy opponent." Leben would prove to be more than worthy, even under the tough circumstances, battling Akiyama in a brutal fight where both men gave as good as they received before Leben scored a shocking triangle choke submission with just 20 seconds left in the fight. Leben would go 1-5 before retiring from the sport, but had cemented himself as one of the UFC's all-time blood and guts brawlers through performances like his showing against Akiyama.

UFC 25 Greatest Fights: Leben vs. Akiyama

"Dana White is going crazy right now!" -- Joe Rogan Chris Leben's incredible submission win vs. Sung Hoon Choo / 추성훈 / Yoshihiro Akiyama / 秋山成勳 / 秋成勳 comes in at #17 on the #UFC25GreatestFights list! Too high? Too low?

Posted by UFC on FOX on Tuesday, March 13, 2018