Clive Mendonca is a difficult man to trace, in part because he has no desire to be found. Five years ago there was even a social media campaign, #FindMendonca, which yielded a solitary photograph.

But Sportsmail has tracked him down, in the week in which everyone is looking for this elusive former striker.

For on Sunday at Wembley, Charlton play Sunderland in a repeat of the fixture voted the greatest play-off final of them all.

Clive Mendonca scored a hat-trick against Sunderland to help Charlton win promotion in 1998

It was in 1998, 21 years ago and with a place in the Premier League at stake, that Mendonca, the Sunderland fan, scored a hat-trick for Charlton in a 4-4 draw before scoring again during an epic 7-6 shootout victory. Death threats followed.

So, where do we find him? In Sunderland, of course. No mobile phone, no email address, just a landline he occasionally answers if he is not on shift at the nearby Nissan car plant.

A dad of two, married to his childhood sweetheart and now a grandad at 50, Mendonca is fascinating company. His upbringing on Wearside, with his mother and four sisters, appears fractured and fractious, yet his character is endearing yet guarded.

In a few hours he will clock on at Nissan and work until midnight. In his own words, there are times when it's 'f****** hard', especially given the adulation of the career he had. So to take him back to that Wembley afternoon — 'the greatest game of my life' — feels like escapism.

Yet earlier, when he walks into the pub where we meet on a sunny morning in Boldon Colliery, his shoulders are slumped, hands in pockets. He does not give the impression of particularly wanting to be here. Then, within a quarter of an hour, he is alive. We have readied the highlights for him to watch, for what we later learn is only the second time in 20 years.

Now he is out of his seat, his shoulders no longer slumped. They are raised, as if pinning a defender, his hands feeling for his opponent. Goalscorers are unique, instinctive individuals.

In this moment, lost in himself, Mendonca is unrecognisable from the withdrawn, long-retired footballer of minutes earlier.

Mendonca was a Sunderland supporter but the striker received death threats from fellow fans

His hat-trick goal plays on the screen, a brilliant volley after he somehow cushioned a bullet-like delivery inside the six-yard box. He swivels, foot raised, and volleys at fresh air.

'BANG!' he booms, his accent an unmistakable Mackem. The replay begins. 'Watch my touch, it's coming at me at proper pace. One touch, the touch of a lifetime. Then, get in!

'My mate was in Mexico, a massive Sunderland fan, listening on the BBC World Service. He says it comes across, "MENDONCA! IT'S WORLD-CLASS FROM MENDONCA!"'

That goal made it 4-4 in the 103rd minute. Earlier, we watch his first for 1-0, a whipped finish after a Bergkamp-esque turn.

'See the turn, I do Jody Craddock a treat there. Pause it now. For me here, time stands still. One on one with the keeper. I've given him the eyes and swept it across my body — I always did that.' Again, he recreates the finish like a kid in the playground, 'Whoosh!'

We press play. Niall Quinn levels with a header and Kevin Phillips lobs in for 2-1 Sunderland. Then, in the 71st minute, Mendonca darts across Darren Williams, controls with his studs and rolls the ball into the bottom corner.

'Look, he can't take me down, he's off if he does. The control with the studs, it's hard that, not being big-headed or owt. I went mad here like, pure emotion.'

Within two minutes, Quinn has made it 3-2, peeling off Danny Mills at the far post. 'Millsy wants shooting. We'd worked so much on Quinny pulling off you. Shocking defending.'

Fifty-year-old Mendonca watched back footage of his famous hat-trick with Craig Hope (right)

Then, on 85 minutes, Charlton defender Richard Rufus heads in for 3-3, and so to extra-time and a Nicky Summerbee smash for 4-3 to Sunderland. Mendonca is on his toes, as if back in 1998.

'All I'm thinking now is, "Get me the ball, I need the ball to score".' His team-mates oblige and, after that touch, swivel and volley, he scores only the second hat-trick in a Wembley final since England's Geoff Hurst in 1966.

Penalties. Mendonca is first up. 'Turn the volume up,' he instructs. 'Listen to the noise, man. That walk up towards the Sunderland end, including my own family, I've never heard owt like it. It was frightening. All I could think was, "Just put it in the f****** net".' Top corner. That took some bottle? 'Aye. Was never going anywhere else, though.'

Then, the iconic gun-slinging celebration in front of the Sunderland fans. 'I regret that. I'm a Sunderland lad. I love Sunderland. If I could go back and change one thing…

'But I'll explain the story. A trialist had got the guns out after scoring in training, just got dead excited. It was hilarious. Every time I scored, the lads said, "Get the guns out". For some reason, I did it then for the first time. I think to myself now, "Why?" It wound them up, I get that.'

After 13 successful penalties, Michael Gray, who went to the same school as Mendonca, had to score to keep Sunderland in it. We watch as he rolls it straight at goalkeeper Sasa Ilic.

'God… our lass could have saved that. You could see his body language, "I don't want to take this".'

Mendonca said in a Sportsmail interview: 'My biggest regret is never playing for Sunderland'

Charlton were in the Premier League. Sunderland boss Peter Reid, who had courted Mendonca the previous summer but signed Phillips instead, approached the man of the match.

'He shook my hand but I had a point to prove to Sunderland that season. I was dying to say, "Why didn't you sign me?" My biggest regret is never playing for Sunderland. I would have loved to play up front in that team with Quinny.'

Not that the Sunderland fans showed him much love after the game: 'There were death threats, aye, and the press found out. I was gutted when the headlines were about that after I'd scored a hat-trick. I took no notice, though. I can look after myself.'

Rumour has long since had it that his mother's windows were smashed in Sunderland.

'Everyone says that, even now, but it never happened. My ma is the type of woman, if you put hers out she'd be straight round to put yours out. Our estate was pretty rough. I heard through the grapevine all sorts was gonna happen to me, but when I came back and walked into the pub, they all shook my hand.'

Mendonca and his wife went on holiday to Cyprus. 'Who do we bump into? Micky Gray! He's gone, "You're the last person I want to see!" But we had a drink and a laugh, although he said, "I had to get away from Sunderland, I just wanted to dig a hole and disappear".'

Mendonca considers the fine line between success and failure. 'It was the greatest game of my life, but if I'd missed the deciding penalty, even after the hat-trick, it would definitely have been the worst.'

Striker Mendonca, pictured celebrating at Wembley, played for Charlton from 1997 to 2002

Mendonca traces the scars on his eyelid and follows the jagged wounds down to his cheek. They are a reminder of just how lucky he was to be alive to influence events in that play-off final.

A few years earlier, he and Grimsby team-mate Paul Futcher had been involved in a head-on car accident in heavy fog.

'Futch thought I was dead. I was the passenger and took the brunt of it. I was knocked out. It was horrible. There was skin hanging off the windscreen.

'You see that scar? Last year, no lies, I picked a chunk of glass out of my face. I was in some state. I was lucky to survive.'

Mendonca's entire life, it seems, has been a tale of survival. Born in London, he moved to Sunderland aged two and has not seen his dad since those early years. He then had the chance to sign for his hometown club as an apprentice.

'The best thing I ever did was get away from Sunderland at 16. My life wasn't the best growing up. My ma had to look after my sisters. I led my own life, really.

'My mates were getting locked up. I was with our lass even then and she was dead upset, but I told her we'd be together, I just needed to get away, so I signed for Sheffield United.'

There were spells at Doncaster, Rotherham and Grimsby before signing for Charlton under Alan Curbishley for a club-record £700,000 in 1997.

'I knew nowt about London. Curbs picked me up and drove me around. He said, "This is Chigwell". Me and our lass loved Birds of a Feather. So I said, "Where do Sharon and Tracey live?" He couldn't stop laughing. '

Mendonca works for Nissan and lives in Sunderland, without a mobile phone or email address

It was at Charlton that Mendonca learned that his uncle, Ivor Mendonca, was a famous West Indies wicket keeper.

'A letter came in asking for his autograph. I was like, "Eh?" I never had contact with my dad, so didn't have a clue. I asked my ma and she said, "Ah yeah, your dad's brother was quite good at cricket!" This fella who wrote the letter said he couldn't find him, so my uncle sounds a bit like me!'

Mendonca scored 28 times in that promotion season and netted another hat-trick in the first-ever Premier League match at The Valley during a 5-0 win over Southampton.

It is why, in a BBC poll in 2004, he was voted Charlton's No 1 cult hero. He won the same honour with Grimsby, the only player to do so with two clubs. Charlton, though, were relegated and Mendonca later retired aged 32 because of a hip injury.

'I had to accept it, but I wish I'd looked after my money. It's hard, going from Wembley to a production line. But that was my fault, I've just got to get on with it.'

We are now taking a walk around Sunderland's iconic Penshaw Monument. So, what does all of this feel like, revisiting the past?

'I never get interviewed, I always keep it to myself. I never watch my goals and there's nothing of football in the house. I just think it's my past life.

'But this, it has stirred the emotions. I'm proud, really proud. That game was my defining moment, all them years of working hard, God repaid me that day. It was just unfortunate for me it was against Sunderland!'