In September 2014, Conor McGregor was just a loud-mouthed upstart with three UFC fights to his name.

His next opponent, Dustin Poirier, was a 10-fight UFC veteran ranked as the promotion’s fifth-best featherweight, a division in which he held the record for most wins and most finishes.

A lot has changed since then.

After his first-round knockout win, McGregor – who is to beat Poirier in their rematch in the UFC betting –  quickly became the biggest star that the UFC has ever known, before the distractions of fame saw him fall from grace.

Poirier, meanwhile, was forced to build himself back up from the bottom, slowly making his way through the lightweight ranks to eventually become interim champion.

Their career paths have diverged completely, and yet they are set to meet again at UFC 257 on Fight Island.

So, how did we get to this point? These are the 10 key moments since the first fight that led to McGregor v Poirier II.

1. McGregor v Mendes | UFC 189 | 11 July 2015

After beating Poirier, McGregor needed just one more fight – a second-round KO of Dennis Siver – to catapult himself into featherweight title contention.

A date with the champ, Jose Aldo, was set for International Fight Week, but a rib fracture saw the Brazilian replaced by Chad Mendes, and the stakes downgraded to an interim belt.

The change of opponent did nothing to temper the build-up, with Mendes more than willing to trade barbs on the mic.

The American even looked like causing an upset, landing several takedowns and unleashing some brutal ground-and-pound which cut McGregor up.

McGregor wasn’t to be denied, though, as he somehow recovered to pepper Mendes with several clean shots before sending him to the canvas with seconds remaining in the second round.

‘Notorious’ had truly arrived.

2. Aldo v McGregor | UFC 194 | 12 December 2015

The UFC wasted no time in rescheduling McGregor’s fight with Aldo, who, at the time, was one of the organisation’s most dominant champions.

The Brazilian was unbeaten in his last 18 fights, and was the only champion the UFC had ever known at 145lb, defending his belt seven times before meeting McGregor.

No one – apart from the Irishman – could ever have predicted what came next.

After raking in a straight left and a side kick to open the fight, McGregor read a left hook from Aldo and slept the champ with a single punch.

Thirteen seconds was all it took – the fastest finish ever in a UFC title fight, and a record that is unlikely to be beaten.

3. Mayweather v McGregor | 26 August 2017

By this point McGregor was one of the biggest stars in world sport – he’d won UFC titles at two weights, and tempted the greatest boxer ever out of retirement for a nine-figure fight.

Mayweather v McGregor was the sporting event of the year and, despite his 10^th-round TKO loss, it elevated McGregor into another level of fame and fortune.

The higher you go, the harder you fall, though, and this was also the point at which his UFC career began to unravel.

Already stripped of the featherweight belt for inactivity, McGregor also had his lightweight title vacated in the months following his detour into boxing.

4. Poirier v Pettis | UFC Fight Night | 11 November 2017

While McGregor was busy fighting for titles and making millions, Poirier was grinding his way back up the ranks.

After moving up to lightweight following his loss to McGregor, ‘The Diamond’ amassed a 5-1-1 record at 155lb to climb to No. 8 in the ladder.

Not only was Poirier starting to rack up the Ws, but he was also establishing himself as one of the division’s toughest and most exciting fighters.

That reputation was only enhanced when he submitted former champ Anthony Pettis in the main event in Norfolk, Virginia – his second Fight of the Night in nine months.

5. Poirier v Gaethje | UFC on Fox | 14 April 2018

Beating Pettis saw Poirier shoot up to No. 5 at lightweight – the first time he had cracked the top five of a division since his loss to McGregor.

Big fights were starting to come thick and fast for ‘The Diamond’, who next faced Justin Gaethje – one of the toughest fighters in the UFC.

Poirier proved he was back where he belonged in a Fight of the Year contender, as both men went toe-to-toe in a back-and-forth thriller.

Despite his front leg being shredded by kicks, and his eyes being poked several times throughout the fight, Poirier stopped Gaethje in the fourth round with a trademark flurry of crisp, accurate punches.

6. Poirier v Alvarez | UFC on Fox | 28 July 2018

Just three months after that war, Poirier was back in the cage for a rematch against former champion Eddie Alvarez.

Their first fight had ended in a no contest after Alvarez landed several illegal knees, but Poirier ended the rivalry in emphatic fashion in Calgary.

At the end of a second round in which Alvarez had dominated on the ground, Poirier got to his feet and once again decimated an opponent with his powerful striking. 

‘The Diamond’ was finally a legitimate UFC contender.

7. Nurmagomedov v McGregor | UFC 229 | 6 October 2018

Despite nearly two years away from the UFC, McGregor was granted an immediate title shot against Khabib Nurmagomedov – the man who replaced him as champion, and one with whom he possessed a deeply personal rivalry.

The Russian was one of the most dominant fighters in the history of the sport, holding a 26-0 record including 10 wins in the UFC.

Many believed this was a step too far for ‘Notorious’ – particularly considering his time away from the sport – and they were proved very much correct as Nurmagomedov dominated and eventually sunk in a neck crank to force the tap.

The fight was marred by a post-fight brawl between the two camps, but even that could not detract from McGregor's new reality: he was no longer the man to beat at 155lb. He no longer had the substance to back up the bravado.

8. Holloway v Poirier | UFC 236 | 13 April 2019

Rather poetically, it was Poirier who was given a chance to cement his fall.

With Nurmagomedov banned for nine months for his part in the brawl with McGregor’s entourage, the UFC booked Poirier into an interim lightweight championship bout against reigning featherweight king Max Holloway.

The feeling before the fight was that Holloway would win – he was a 1/2 betting favourite – but Poirier produced yet another excellent performance to secure a unanimous decision.

After 22 fights over eight long years, ‘The Diamond’ finally had his hands on UFC gold – even if it was just the interim title.

9. Nurmagomedov v Poirier | UFC 242 | 7 September 2019

As interim champion, Poirier was next in line to face Nurmagomedov, whose ban had come to an end.

No one gave him the chance against the returning champion and his suffocating style, as Poirier entered the fight as a 4/1 underdog, and those predictions were spot on.

Nurmagomedov dominated through three rounds, wearing down Poirier on the mat, before finding the rear naked choke.

Having spent so long rebuilding his career and fighting to prove himself as an elite UFC contender, Poirier would have to do so once again. 

10. McGregor v Cerrone | UFC 246 | 18 January 2020

After his loss to Khabib, McGregor’s inactivity saw him drop to No. 4 in the UFC lightweight rankings, putting him well out of contention for another shot at the title.

In March 2019, he claimed he was retiring from the sport – not for the first time – and he became an afterthought in the division he once reigned over.

McGregor couldn’t stay away, though, and eventually returned to the Octagon at welterweight against veteran Donald Cerrone 16 months after his previous fight.

His time away didn’t diminish his skills or his appeal, as McGregor dismantled Cerrone within 40 seconds at an event that exceeded 1.3m pay-per-view buys.

The rematch | UFC 257 | 23 January 2021

So, here we are.

Another year out and McGregor is back, this time against a legitimate threat in Poirier, who is a totally different fighter to the one he faced in 2014.

Some things remain the same, though.

Poirier heads to Fight Island above McGregor in the rankings, at No. 2 and No. 4 respectively.

The American remains one of the classiest operators in the game, while the Irishman has retained the bravado and arrogance that helped make him a star.

The stakes of the fight are much the same as the first time round, too – with Nurmagomedov’s future up in the air, the winner of this fight will surely be in contention for the title once again.

Everything points towards an absolute classic.

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