Five fighters are in contention take the place of the Russian and become the next champion at 155-pounds.
Khabib was so dominant over his challengers that there is not one obvious selection or fight for his old belt.
Here, Sportsmail takes a look at the fighters who could pick up the mantle as a new era for the lightweights begins.
Khabib Nurmagomedov leaves the UFC as one of the greats and leaves a title vacant
The Russian will have a number of fighters scrambling to take over his former position
The American was ahead on two of the three judges’ scorecards but in truth it was a Khabib masterclass on Fight Island.
Gaethje is in good company in coming up short against the wrestling phenomenon and he is still in a strong position despite the defeat.
Perhaps McGregor knows that as he took a swipe at Gaethje on social media for his performance in a now deleted post.
Justin Gaethje will feel he should still be at the front of the queue for another title shot
The Irishman wrote: ‘Dustin KO’d you, as well as your wrestling/grappling and overall fear of the central positions being truly embarrassing tonight, Justin.’
But Gaethje is ready and willing to take on McGregor for the belt, saying: ‘With him retiring, I’m No 1.
‘Poirier and McGregor are going to fight. They haven’t made it official, so if McGregor wants to bounce out and get the belt, then I’m right here.
‘If they want to give it to someone else, then so be it. But I’ll be ready. I’m ready to fight again. This is my job. This is my life. I love it so much.’
One possibility is that the UFC make Gaethje fight one more time before he can compete for the title again, possibly against the winner of Poirier and McGregor.
If this is the case, then Michael Chandler would be in with a great chance to fight ‘The Highlight’.
Gaethje (right) landed some punishing leg kicks on Khabib but was undone by the wrestling
The new kid on the block has actually already been around a bit.
Chandler made weight on Fight Island and was the ready and willing stand-in if Gaethje or Khabib dropped out.
The former Bellator lightweight champion has only just signed with the UFC but clearly the organisation rate him highly.
Match-makers may make him prove himself against someone below top tier first.
Michael Chandler made weight as stand-in for UFC 254 but he ultimately wasn’t needed
The likes of Paul Felder, Charles Oliveira or Dan Hooker are all in with a chance but the problem of what to do with Gaethje might be solved by Chandler.
It would be incredibly harsh to make the defeated challenger line-up against someone ranked so far below him and Gaethje is likely to prefer the Chandler fight. The 34-year-old is untested against the very best but now he’s at the big show a sink-or-swim encounter with the No 1 ranked lightweight may serve both men well.
It would be unlikely to take place this year and given that the UFC have McGregor and Poirier pencilled in for January 23, putting the fight on the same date would be a stroke of genius.
That would leave both men enough time for a full training camp to kick off 2021 in style.
A short tournament format would capture the imagination of fans and build some hype around the lightweight division. Nobody wants to just be handed a belt without having earned it and the fans don’t respect it, as Daniel Cormier found out in the Jon Jones saga.
Part of McGregor will be desperately disappointed at Khabib’s retirement as it seems he will never have another chance for a rematch.
Another part of him might well be relieved he won’t have to go through the Russian to claim back the lightweight title.
Poirier beat Gaethje and McGregor beat Poirier in their first fight, there’s nobody really for the Dubliner to fear here.
He has been desperate to get back in the octagon and retired out of frustration at the UFC not matching him up behind closed doors during the coronavirus pandemic.
Conor McGregor may well believe he has a straightforward run to retain the lightweight belt
They will want to keep him busy now as without Khabib, they need a pay-per-view star to carry some of the weight.
Nobody is bigger in that regard than McGregor and if he goes ahead and defeats Poirier for the second time, that is likely to either be for the interim title or a shot at the belt.
One issue is the weight. McGregor has looked solid at welterweight and dispatched Donald Cerrone at 170-pounds in January.
He may feel his future lies there but White has already said he’ll be fighting Poirier at lightweight as that makes the most sense.
If McGregor does string together a couple of wins to reclaim his lightweight tile, some of the gloss will have gone as he didn’t win it back from Khabib.
But if anyone can sell fans on a new dawn for the lightweights and life after the Dagestani, it’s McGregor.
McGregor (left) made light work of Donald Cerrone in January but retired in the summer
Another one of Khabib’s victims, Poirier failed to agree terms with the UFC over a fight against Tony Ferguson in recent weeks.
That led to him and McGregor going back-and-forth on social media and agreeing to a fight.
The UFC have given it the green light and although McGregor wanted it before the end of the year, he has accepted it taking place in late January.
Poirier bounced back from his defeat by Khabib with a creditable win over Hooker and if he was to exact revenge over McGregor it would be the perfect way to stake his claim.
Dustin Poirier beat Dan Hooker after losing to Khabib and he is now in the title conversation
That would also leave McGregor with nowhere to go in terms of a title shot but ‘Diamond’ is one of the most popular fighters in MMA and has plenty of good will.
It would be gut-wrenching for Poirier if the UFC decided to simply match McGregor and Gaethje for the vacant lightweight title, but that seems unlikely.
It is a stretch to imagine the organisation putting a title on the line for his fight with McGregor but the winner, if it goes ahead, would undoubtedly be next in line.
Where next for ‘El Cucuy’? This is a tricky one. Of the five main contenders, he’s the one at the back of the queue having been well beaten by Gaethje in May.
Ferguson did accept that change of opponent on short notice and had more than earned a title shot before then, only for it to keep falling off against Khabib. He remains one of the most entertaining fighters in the division and if Gaethje isn’t matched up with Chandler, that seems like a logical next opponent.
If not, then Ferguson will either have to bide his time and wait for the picture to become clear or take on one of the division’s rising stars.
The unorthodox striker is usually happy to face all comers but that may hinder him in this case.
At 155-pounds, the UFC have so much talent.
Tony Ferguson was well beaten by Gaethje (right) and could find himself as the odd man out
Khabib’s protege Islam Makhachev is highly thought of and hasn’t fought elite level opponents just yet, he would jump at the chance to face Ferguson.
Oliveira and Hooker are also both in their prime and hungry for more while Carlos Ferreira is on a six-fight winning streak.
Drew Dober, Gregor Gillespie, Kevin Lee and Beneil Dariush are all still floating around in the top 15 and on their day could beat anyone.
A win against any of those knocking on the door of the top five would surely put Ferguson in a strong position again. But defeat could be catastrophic for the 36-year-old who would then have tricky banana skin fights with rising stars as he enters the autumn of his career.
On Saturday, White said: ‘Don’t ask me about the future, I don’t have a clue right now.’
There should be clarity in the coming weeks as the UFC and lightweight division move on with life after Khabib.
The UFC must now fill the considerable void left by Khabib after his decision to walk away