Mark O’Brien is making a point. He recalls periods from the third-round win over Leicester when Newport got the ball down and showed some swagger. He remembers a good few patches in the fourth round against Middlesbrough, too.

‘We can play,’ he tells Sportsmail. ‘We can do all that — we’ve shown we can. We have good footballers here.’ Then there’s a delightfully long pause.

‘You know what, though, maybe this time we might have to do it the other way,’ he says. ‘I mean, look at them. It’s Man City. It’s Pep Guardiola — mad that he’s going to be here. Maybe it wouldn’t be the smartest thing to try to beat them at their own game. Just a hunch, you know — it might have to be scrappier.’ 

Arguably no player within Newport County is more entitled to believe than Mark O’Brien

O’Brien’s tale is uniquely dramatic, considering how terrifying it was in the early years

Now he’s laughing. They all are in these parts. It’s Newport, assembled at a cost of £50,000 from cast-offs and strays, up against Manchester City with a starting XI at around £470million.

Yes, the League Two club put a lot of stock in the leveling powers of their pitch at Rodney Parade, but it is hard to envision the quantity of rain or mud needed to balance the scales on Saturday.

Yet still they dream. No club has a greater right to do so after what they have been through and arguably no player within Newport County is more entitled to believe than O’Brien.

The 26-year-old centre half is not alone here in having a story — Robbie Willmott stacked shelves in Tesco, Jamille Matt is a psychologist, David Pipe went to prison and reformed himself, Joe Day missed the birth of his twins during the fourth round replay against Middlesbrough, and almost all of them have been rejected multiple times in reaching this point.

Yet O’Brien’s tale is uniquely dramatic, considering how terrifying and bleak it was in the early years and how delightful it has been since he asked Newport for a trial at the end of 2016. 

The League Two club put a lot of stock in the levelling powers of their pitch at Rodney Parade

He spoke about how delightful it has been since he asked Newport for a trial at the end of 2016

The logical starting point is his time as a teenage prodigy at Derby. They raved about him once upon a time: the boy who had left his family in Dublin aged 15 and made his debut in the Championship at 16. With Nigel Clough taking a shine to him, he was on his way. Then he wasn’t.

‘I made my debut at the end of the 2008-09 season and after coming back for the new season we had these routine scans and they just said one day I had a faulty valve,’ he says. ‘The fitness coach had always said my heart rate was really high and I put two and two together and asked if it was down to the valve.

‘I was taken to see the specialist and got told I wouldn’t need an operation for 60 years. I then saw another specialist who did an MRI and said on a scale of 1-10, bleeding back into your heart is about seven. Suddenly alarm bells start.

‘They were like, “You might not need an op for 20 years but we need to keep an eye on it”. Then we were referred to a surgeon to get his opinion and we were in this tiny room — me, my parents, the physio and the surgeon — and he had a model heart in his hand.

‘He said, “Your heart is three times the size it should be and if you don’t have this operation soon you’ll die this year”.

‘I’m like, “OK, what was that now?” Oh my god. I’d gone in weeks from making my debut at 16, to needing surgery in the next two weeks or maybe dropping dead on the pitch. What does a kid do with information like that? My only question was could I still play after I had the surgery? He said he couldn’t guarantee it.’

 It is hard to envision the quantity of rain or mud needed to balance the scales on Saturday

O’Brien recalls periods from the win over Leicester when Newport got the ball down

O’Brien had the seven-hour, open-heart operation to insert a pig valve in October 2009.

‘I came around in intensive care and I was in hospital for a week. At first I couldn’t walk from my bed to the door without stopping and I was on seven tablets a day for four months. Nigel Clough was fantastic with me, really supportive, but it’s hard to keep away dark thoughts about your career in that situation.

‘I just remember telling myself if I ever made it back from that surgery, I would never doubt myself again.’

They are words that have been severely tested. O’Brien made it back into the Derby squad seven months after surgery, but across a year he played just two games and it was only in the 2011-12 campaign that he made his breakthrough with 20 appearances. Then his cruciate ligament snapped in training.

Newport, assembled at a cost of £50,000 from cast-offs, are up against Manchester City

Pep Guardiola’s Manchester City have a starting XI that cost at around £470million

‘Not great luck, hey?’ he says. It seems a fair summary of his time at Derby, where he also had an ankle operation, a hernia and a micro-fracture in a knee before leaving when his contract was up in 2015.

He was signed by John Still for League Two Luton, but he was frozen out within a year by then-boss Nathan Jones.

‘For whatever reason they didn’t want me and I was training with the Under 18s,’ he says. ‘I went on loan to Southport because I just wanted to play. It was a hard time. 

‘You have moments where you think, “I just want to go home to Dublin, pack it in”, but they passed. That again was a bit about the heart stuff. I’d get down and think, “You have come back from worse than this”, but it was hard. I needed to get out of Luton so I called someone I knew at Newport and asked for a trial.’

After showing up on a short-term deal in January 2017, the upturn in his career after so much difficulty has been astonishing.

He had left his family in Dublin aged 15 and made his debut in the Championship at 16

O’Brien had a seven-hour, open heart operation to insert a pig valve in October 2009

These days O’Brien rarely goes a week without a fan approaching to talk about the only league goal of his career. It was the 89th-minute winner on the final game of the 2016-17 season, which not only kept Newport in the Football League but possibly kept them in existence.

‘It’s funny,’ O’Brien says. ‘A lot wasn’t great for me in my career. Then I came here, started playing every game and I was already finding myself happier again in those first few months. Somehow I scored the goal on the last game of the season and it created a whole new story for me. I mean, I never score. Mad, you know.

‘That goes in and suddenly you feel it is the best game in the world. Your luck starts changing and you realise it is why you play.

‘Everything at Newport, with these players, this manager, it has just been so great. The last couple of years — it just makes you glad you stuck at it.

‘We have all had our knocks and now this, we are still standing and about to play Manchester City. People won’t give us a chance, but who cares?’