Despite his fair share of controversy outside of the Octagon, Conor McGregor has been a thorn in many fighter’s road to glory.His left hook is usually too hard for anyone to take, with Jose Aldo, Dustin Poirier and Nate Diaz each perfect examples of those who have fallen to McGregor’s trademark hit.Fans have not seen McGregor in the Octagon for almost a year and are eagerly looking forward to his second career fight against Poirier this Saturday on Fight Island.One thing Poirier will be looking to improve upon from his first bout with McGregor is how to better deal with the Irishman’s hard-hitting left hand. But just how hard does McGregor punch with that infamous left hand of his?In the build up to UFC 205, the promotion company set up a punching machine for fans to see how hard they hit.According to what was shown on Snapchat of the machine’s top scores, McGregor’s score was higher than Stephen Thompson and Eddie Alvarez, but just shy of former welterweight champion, Tyrone Woodley.Some of McGregor’s former opponents have spoken out on his punching power in various interviews.Floyd Mayweather:The Irishman fought the American legend back in 2017, McGregor’s first ever boxing match. Mayweather took the victory as we all know, and had some words about McGregor’s punches:“As far as his punching power – he’s solid,” Mayweather said in a press conference after the pay-per-view main event.“I’ve felt it before, so that’s why I kept coming straight ahead. Obviously, it wasn’t the type of power to say, ‘I can’t come forward.’ Because if it were that type of power, I wouldn’t have come forward.”Paulie Malignaggi:Malignaggi was McGregor’s sparring partner ahead of the Mayweather fight. The Italian-American boxer arguably saw the best of McGregor’s boxing abilities, especially given that Malignaggi was supposedly knocked down by McGregor during a sparring session.When addressing how hard McGregor hits, the Magic Man said: “Do you want to know if he hits hard? Yeah, I mean, he’s not a weak puncher. I’ll say that.“People are dying for me to say, ‘Oh he hits hard!’ Oh, his big left hand.’ Listen, if Conor hits you, you’re going to feel it. He’s a grown man.“I’d say he’s an above average puncher. If he lands a shot with 10 oz gloves, it will probably get your attention. Is it ‘Oh my God power’? No, ‘Oh my God power’ is very rare.”Nate Diaz:After McGregor’s shock loss to Diaz in March 2016, the Irishman redeemed himself a few months later at UFC 202 with a majority decision victory.While the two are 1-1 in their matchup history, Diaz was left bloodied and battered by the Irishman, even after their first bout.“I had just fought in December and I had a cut [above my eye] from that Michael Johnson fight,” Diaz told UFC on FOX. “It pretty much split right open.“I didn’t really feel it at the time but I looked back on the fight and thought ‘Oh f*ck’. It was a real nice uppercut.“My eye got blurry for a minute. In between rounds, they wiped it with ice. Then, in the second round, the ice water and blood came into my eyes and I couldn’t see s***.”Eddie Alvarez:McGregor’s UFC 205 knockout blow to Alvarez will forever be iconic. After the fight, Alvarez was full of praise with regards to the Irishman’s dominance:“It was more his speed.“I got dropped a couple of times, the first time I got dropped I remember being on my butt and thinking, ‘Wow, that was quick. Whatever that was it was fast’.“I’ve been there plenty of times in my career where I get dropped. ‘I don’t panic; I keep my composure and get back up.“His speed and timing were very good; you could tell he’s got years of boxing behind him.”Dustin Poirier:Poirier and McGregor square off this weekend, so we’ll keep this one short.The American was asked on Twitter who was the hard-hitting fighter he’d ever faced, and Poirier’s answer was none other than The Notorious himself.Owen Roddy:Roddy is McGregor’s striking coach and has worked with the Irishman since 2007.He has definitely had the best evidence regarding McGregor sheer power when it comes to punching.Roddy said: “He has really long arms and he uses them very well to keep people at bay. He also has very fast twitch fibres in his muscles.“Conor has a unique style. A wide stance is not common in boxing but it is in combat. Conor is like a sprinter. He is fast and explosive, but it is hard to maintain that for five rounds.“Conor often doesn’t need to last that long because of his habit of putting people to sleep.“He has unbelievable power. When I used to spar with him, almost every punch felt like it was from a man twice his size.”Jose Aldo:In one of the craziest (and shortest) UFC fights in the last few years, McGregor took the featherweight title all for himself after knocking out Jose Aldo after just 13 seconds.The speed of the left hook was too much for the Brazilian to handle, and fans had to take quite some time to process what had just occurred.

Aldo however, was not that impressed with McGregor’s punching ability.

“He has a good punch, but he cannot say that he is the biggest puncher, and the MMA gloves are tiny. They are four ounces.”

Firas Zahabi (Georges St-Pierre’s coach)

A McGregor and St-Pierre superfight has been rumoured for quite some time now, especially given McGregor’s willingness to fight across different weight classes.

Despite many seeing this potential fight going St-Pierre’s way, the Canadian’s coach spoke highly of the Irishman’s power as a fighter:

“He’s got the touch of death in his hands,” he told The Express  “He knows what he’s doing; he’s highly intelligent, highly captivated, he’s extremely dangerous.

“And I don’t think he fears anybody. So I think him and Georges would be a phenomenal fight.”