Pitch invaders in football are pretty commonplace, truth be told, but it's extremely rare that said pitch invaders are former professional athletes themselves.

Yet, that's exactly what happened at the weekend. As it turns out, the elated Manchester City fan who mobbed Erling Haaland after his opener against Sheffield United is actually a world-champion boxer.

Pep Guardiola's side returned to the top of the Premier League with a hard-fought 2-1 victory over the Blades. Haaland opened the scoring in the second half before Jayden Bogle seemed to have rescued a point late on. City, however, found another gear in the closing stages and secured all three points courtesy of Rodri's strike in the 89th minute.

The result means City are now the only side in the Premier League with a 100 per cent record this season and the scary thing is, they haven't even been at their best. Indeed, with new signings still finding their feet, an injured Kevin De Bruyne and the likes of Ilkay Gundogan and Riyad Mahrez no longer at the club, City are only going to get better.

Haaland mobbed by world-champion boxer

Despite Rodri's later winner, it was Haaland who stole most of the headlines. The Norwegian striker was uncharacteristically wasteful and missed a number of fine chances – including a penalty. But even on a rare off-day for the forward, Haaland still found the back of the net, eventually heading home from a Jack Grealish cross.

And as the Man City fans celebrated at Bramall Lane, Haaland was embraced by none other than Terry Flanagan – once the holder of the WBO lightweight title between 2015 and 2017.

The 34-year-old, who is now retired, saw his opportunity after Haaland's goal and didn't think twice – leaping onto the striker's back as the rest of the City team rushed to celebrate. While it's unclear whether Haaland is familiar with Flanagan, he seemed pretty unbothered by his presence and even allowed the ex-boxer to hug him again briefly before he was taken away by stewards. Check out the moment below.

VIDEO: Terry Flanagan mobs Erling Haaland

Who is Terry Flanagan?

Originally from Manchester, Flanagan had his first professional fight back in 2009 and soon began to rise through the ranks. He won the Prizefighter lightweight tournament in 2012 and held the British lightweight title in 2014.

In 2015, Flanagan stepped up to fight American Jose Zepeda for the vacant WBO lightweight belt – a title left vacant by Terence Crawford. Flanagan won via a technical decision to claim the title before defending the belt at the Manchester Arena against Diego Magdaleno later that year.

Flanagan ended up defending the belt a further four times, before challenging for the light-welterweight title in 2018. However, he lost via a split decision to US fighter Maurice Hooker.

Overall, Flanagan has a professional record of 36 wins and just two defeats, though he last fought way back in 2019.

His love of Manchester City has always been public knowledge and he has even conducted interviews with the club, which can be viewed on the City website.

Unfortunately for Flanagan, however, his pitch-invading antics might see him get a lengthy ban from the Eithad, depending on how the club view the situation.

What other celebrity sports fans are there?

You might be surprised to know that a plethora of athletes and celebrities in general are big fans of Premier League clubs.

Granted, not many of them will be making it to away days and evading security to invade the pitch any time soon, but a large number are still ultra-passionate supporters.

And when we say celebrities – we're talking A-list here as well. Take Margot Robbie, for example. To the majority, she is best known as the star of hit films like Barbie and The Wolf of Wall Street, but deep down she's a fan of Fulham.

That's not even the weirdest one. Believe it or not, WWE icon Triple H is a West Ham supporter and has even been pictured outside the London Stadium.

"West Ham is probably the closest to what we do, with the passion of their fanbase and their loyalty, right? That's the closest to what we do," he once said.

Check out each Premier League team's most famous celebrity fan below.

READ MORE: Each Premier League team's most famous fan

Can Haaland hit the same heights as last season?

Moving away from celebrity fans and back to the real star of the show in Haaland. The striker is a contender to win this year's Ballon d'Or owing to his exceptional season last year, where he broke the Premier League goal-scoring record and notched more than 50 goals in total.

The question is, can he get close to those numbers again this season? On current evidence, yes is the answer. We may only be three games into the new campaign but Haaland is already the joint top scorer in the league and that's despite his missed penalty against the Blades.

While the Norwegian was criticised for missing a handful of chances at the weekend, he still managed to score, which seems to be a recurring theme.

Speaking afterwards, Man City assistant manager Lilo, who has assumed responsibility of the team at the moment while Guardiola recovers from back surgery, said of the striker: “Today would have been difficult for any striker, how it played out in the first half.

“Of course, there was the situation with the penalty, which is frustrating for anyone, but that could happen to any striker, not just Erling.

“What it does show is that, and not just because he scored, because he came close on a couple of other occasions as well, came really close with [another] header, that it really shows his mental fortitude to keep going and keep going. That’s something that’s really difficult to find and he showed it throughout."

He added: “He’s a very young lad and his mindset is so good that, OK he’s missed a penalty, but he’s come back now and he wants to keep going and keep trying to score these goals.”