Derek Riordan arrived at Celtic with the world at his feet... then the rug was whipped from underneath them.

There was a sense of genuine excitement when the Parkhead side signed Riordan on a pre-contract agreement in May 2006. The club felt that they had captured one of the brightest attacking talents in Scottish football for many years.

At one time Riordan - crowned the young player of the year and the SFWA player of the year in 2005 - was the third Scottish Premier League striker for career goals behind Celtic and Rangers forwards Henrik Larsson and Kris Boyd.

Riordan was seen as arguably the best natural talent of Hibernian's 'golden generation'. He had been the Easter Road side's top marksman for three consecutive seasons and had forged a fearsome reputation as not only a great goalscorer, but a scorer of great goals.

So when then Celtic boss Gordon Strachan came knocking on his mother's door it was a no-brainer to put pen to paper and join the men from Glasgow's east end.

"When Celtic come calling you don't knock them back," Riordan, who is out of football altogether and has a landscaping business, told TCW. "It was close to home in Edinburgh and I just thought it was the perfect opportunity to progress my career.

"Gordon Strachan even came to my mum's house to sign me. After speaking to him I knew I wanted to. My mum's side of the family are all Celtic supporters anyway, total die-hards. That helped me with my decision.

"Strachan couldn't have been any nicer but every manager would probably be like that if other clubs were trying to sign you. He was trying to butter me up, that's for sure, but it worked."

What made it all the more pleasing for Riordan when Strachan finally netted his man was the fact he had been on the radar of city rivals Rangers.

The Light Blues saw a bid of around £400,000 rejected while fees had also been agreed with Cardiff City, Lokomotiv Moscow and German sides Kaiserslautern and FC Nurnberg. The home bird spurned them all to stay close to his family. 

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Thankfully Celtic made their move and signed him on a deal worth £150,000 - but not before the Rangers interest had him in a cold sweat.

"I had the chance to go to Leeds," Riordan recalls. "I should probably have gone to England. When you go down and sign for a club like Leeds you can make a good living and have a good career and you can bob around a few clubs doing your thing.

"Cardiff, Kaiserslautern, and Nurnberg all wanted me back then too. I met the guys from Nurnberg in a house and they were really strict and that just put me off and that move wasn't for me.

"Rangers wanted to sign me as well. Fortunately, I didn't have to make that choice as they never offered enough money. My family weren't happy. I was glad that I never had to make that decision.

"It would have been such a difficult one to make if I had to choose to sign for Rangers because of my mum's side of the family being huge Celtic fans. I don't know if I would have done it. I will never know as I was never put in that position - I am grateful that I wasn't. The ball was never in my court and thank goodness for that.

"I was 23 when I moved, I am 39 now and, transfer-wise, I think it was really difficult to get a move to a club like Celtic back then. I think sometimes players get easy moves now in Scotland.

"I did have the choice of a lot of big clubs back then. I wasn't really fussed about money and stuff. I just wanted to be close to home and that is why I signed for Celtic. It was never about money for me although I did later try my luck in China as that was big money and the chance to go abroad."

Walking into a Celtic dressing room with big characters such as Stiliyan Petrov, Alan Thompson, Bobo Balde and John Hartson would have been daunting - but one, in particular, took Riordan under their wing... and ensured he had a nickname in the changing room.

"I loved Neil Lennon," he said. "I got on really well with him. I sat next to him in the dressing room and I liked him as a person. I thought he was a brilliant guy.

"Lenny had his days when he was as moany as fuck but people said the same about me. My nickname was Victor Meldrew in the Hibs dressing room and that kind of stuck with me at Celtic. Lenny and I were both kindred spirits in the moaning sense.

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"I used to apologise to players before kick-off and say sorry for the amount of moaning I was about to do during a game. The players understood that. I got on so well with Lenny in particular. He was just a great guy but it was probably because we both loved a moan and a complaint."

At the club around the same time was one Shunsuke Nakamura, who Riordan christens "the best he ever played with". He revealed the two used to practice free kicks together regularly after training.

"It was quite good because I would be involved in the team shaping, especially in the run-up to Champions League games, and I got to hit a lot of free kicks," Riordan recalls. "I tended to score a lot of goals when we did that in training and so did Naka.

"He was the best player I have ever played with. He was brilliant. He never lost the ball and his technical ability was off the charts."

Yet rumblings of discontent could soon be heard when Riordan failed to force his way into the first-team despite manager Strachan labelling him the best finisher at the club. The former striker felt that he was being constantly overlooked in favour of other forwards at the time - particularly Kenny Miller.

Riordan said: "The manager can say what he wants to you, whether it's the truth or not. I rattled his door a few times and he would say 'if so and so is not playing then you'll be playing'. We would come to a game and that player would not feature and I still wouldn't be playing so I would ask him why he was talking rubbish.

"The thing I always remember is that Kenny went something like his first 10 games without scoring for Celtic and I am just sitting there thinking 'how the fuck am I not getting a game?'

"I understand that people take time to settle in and sometimes it doesn't work for players at certain clubs but you've got to get a fair chance in the first place.

"The stats showed that I could play and score goals.  It is not like I never did it or couldn't do it because I did. But you have got to get chances, especially at a club like Celtic. I scored on my first start against Motherwell and I just know that if I had played for the majority of the season then I would have been trying to finish the season as the top goalscorer.

"But I could be here all day moaning about Gordon Strachan and my time at Celtic. It is what it is. You can only play the hand you are dealt. I can't help what happened, if that makes sense. 

"It is like any job if the boss and you don't see eye-to-eye you are not going to last or do well are you?"

Celtic Way:

Riordan says he can pinpoint the exact moment that his relationship with Strachan soured and went south.

He was substituted in the 2007 Scottish Cup semi-final at Hampden Park - for Miller - and his frustration boiled over. 

It didn't help either that, despite being signed as a striker, Strachan constantly referred to Riordan as being in competition with wide players Shaun Maloney and Aiden McGeady.

He said: "When I went to Celtic at first he told me not to worry about Maloney and McGeady but managers can tell you what you want to hear. It doesn't matter.

"I wanted to play in attack with Jan Vennegoor of Hesselink. I always seemed to do alright when I played alongside him. Strachan saw me as a left-sided midfielder - which I wasn't, because I was not the best defender. 

"I remember I played the Scottish Cup semi-final in 2007 against St Johnstone and he took me off early for Kenny Miller. I fell out with him because of that. I was an unused substitute in the final. It all went downhill from there."

By the 2007-08 season, Riordan decided to go public with Strachan's treatment of him and spoke to the press.

"I genuinely don't know what he didn't like about me," Riordan added. "I ended up training on my own and Bobo Balde was in the same situation at one point. He was shunned by the manager too.

"Bobo was actually a great guy, a lovely man with a heart of gold. Everybody was all right at Celtic - I still speak to Broony (Scott Brown) and I still speak to Lee Naylor from my time at the club too.

"I don't know what happened with Strachan. It was just strange. I kept myself to myself."

Despite his stormy relationship with the manager, Riordan did enjoy some highs at Celtic. He won the Scottish Premier League title in 2006-07 and again in 2007-08 although the club never struck up a medal for him the second time around because he had not played the required amount of games. That still irks Riordan to this day.

A notable contribution was made in a crucial game though. The striker came on as a substitute against Spartak Moscow in the Champions League qualifiers and scored in the penalty shoot-out that helped take the club into the group stages. Riordan deems it the most pressure he had ever felt in his career.

"It was nerve-racking. The biggest pressure I have ever known," he recalled. "It didn't help that I wasn't playing a lot either.

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"The manager asked me to go on with five minutes to go and get a goal or at least be on the park for extra time and take a penalty if it came to that, which it did.

"That was real pressure. You have to cope with that at a club like Celtic. Luckily enough the ball went in and I was delighted we qualified - it was one of the few brilliant nights I had in my Celtic career."

That match is best remembered for the iconic image of club legend Tommy Burns leaping in mid-air and diving into the Celtic pile-on as the players celebrated their success.

Riordan insists that it was guys like Burns who kept his spirits and head up during his dark days at Parkhead. He revealed that one of the last conversations he had with Burns before he sadly passed away occurred at Barrowfield.

The ex-Celtic player and manager was at pains to explain why Riordan had not quite made his mark or an impression on the first team under Strachan and he was bemused by it all.

"He was a magnificent guy," Riordan said. "I got on extremely well with Tommy. I remember him talking to me and it might even have been the last conversation I had with him at Barrowfield.

"I was training on my own and Tommy said to me 'I don't know what's happening Del, son, I really don't. You just need to try and keep your head up at all times.'

"He was a wonderful man who always kept my head and my spirits up. I don't think anybody connected with Celtic has a bad word to say about Tommy or never had time for him. He was a real legend, the best."

It mightn't have panned out the way he expected at Celtic, but Riordan insists he is not bitter about the experience.

Having seen the likes of former team-mates Scott Brown, Kevin Thomson and Steven Fletcher carve out successful careers in the game, you would be forgiven for thinking that even a small part of him would get resentful, angry or jealous at what might have been.

But Riordan said: "Everybody is different. Players have different personalities and put up with stuff and maybe I am different. I don't know how things work sometimes. You can go to some clubs and not play and that happens in football. Players can go to clubs and be absolutely shite and then they could go elsewhere and win a move to Manchester United. That's just the way football works.

"I am not a bitter person and I would never wish any bad luck or fortune on players I played with or was brought up with. Thommo and Broony are brilliant players and I say well done to them for what they achieved in their careers."

Riordan was good enough to sign for Celtic. He made a total of 32 appearances for the club and scored eight goals. It is a scant reward for a player of such sublime and genuine natural talent.

Riordan said: "Celtic are a massive club. They are known worldwide. I signed for Celtic to win stuff and winning the league was great. The only downside was not playing as much as I could have in my time there.

"I played for Celtic and I won the league and the Scottish Cup - not every Celtic player can say that."

How does he sum it all up then? By pointing to how much the club means to his family.

"My family really are massive fans - so much so that I once spread my uncle, Terence McGovern's, ashes on the Celtic Park turf for him," Riordan said. "I sneaked them onto the pitch while I was playing for Hibs. I had them in a wee bag and Garry O'Connor and I tramped them into the grass. 

"You are not allowed to do that but it meant a lot to me to do that for my uncle."

Riordan's Celtic career and his relationship with Strachan remain an enigma. Only the two men themselves know the whole truth and nothing but the truth.

The supporters believe to this day that he deserved a better chance, a fairer crack of the whip. Riordan's Celtic chapter is a classic sliding doors moment; a genuine case of 'what if'.