Although not one of the greatest goals he scored for his country, nor one of the most significant, his well-rehearsed celebration in front of Ireland's travelling supporters will go down as one of the most memorable moments of the Fulham winger's international career.
If Ireland do return to the international stage this summer, it will be 10 years since Duff delighted Irish fans across the globe. But it turns out he had quite an impact on football followers from the Far East too.
Take a bow, son! Duff celebrates his goal against Saudi Arabia in Yokohama
His Fulham team-mate Stephen Kelly revealed: 'I think Duffer has the biggest majority of Asian fans because of that signature bow.
'It is amazing the number of Asian fans who come over to him and come to the ground to see him.
'It's unbelievable the respect he has because of that, although he gets a little bit of mickey taking from the lads over it.'
So does he enjoy the attention? Kelly laughs. 'You know Damien,' he says. So that'll be a no, then.
Kelly was just 18 and among the youngsters at Spurs dreaming of a future in the game when Ireland last made their entrance on the world stage.
He watched the drama from the Far East unfold in the Tolka Rovers clubhouse with future wife Helga, herself a basketball player at the club. They were in Phoenix Park to welcome Mick McCarthy and the troops home.
No wonder he understands what is at stake as the Republic of Ireland prepare for play-off number seven against Estonia this week.
Magic moment: Duff scores Ireland's third against the Saudis (below)
'I was living every kick of every game,' he said. 'You can't help but get into it.
'I know what it was like when the team went to that World Cup. I was there cheering us on with all my friends and family so if we get there now it would be the same as that again.
'The way the country is now, with a lot of things happening that are not looking good, I think it would be a great boost for the country if we could qualify.
'It would put a smile on people's faces and people could focus on something else, away from the negatives.'
Kelly will keep his place in the Irish back four this week with John O'Shea absent and he has now played across the defence during the Euro 2012 campaign.
The former Birmingham defender, who captained the Ireland team in the Aviva Stadium last season, has had to be patient to make his mark in Giovanni Trapattoni's side.
But a place in the squad which will travel to Poland and Ukraine awaits.
Irish eyes: Ireland are favourites to win the play-off
Kelly said: 'I played the last game, obviously at left back, but now I have the chance to play at right back. As they say, some person's misfortune is another person's gain.
'It's disappointing not to have Josh in the team and the squad as he is such a big and experienced player.
'But for me, hopefully it's another chance for me to play and to continue on the good run of form I have had recently.
'I have played an awful lot of games in this campaign now in the last couple of months and I have really enjoyed it.
'I feel I have contributed a lot to what we have done and what we have achieved so far. Hopefully, I can continue in that vein and in the next couple of games do that again and get us to a championship. That would be amazing.
'I have been far more involved. I came into the squad when I was 19 and 20 and been in it since and I would probably not have as many caps as I would like or should have.
'But this campaign has been good for me as I have had the chance to play in the big games and let me stamp my mark and show people what I can do.'
At Fulham, Kelly has been used more for the club's Europa League campaign than in the Barclays Premier League.
An injury to Czech defender Zdenik Grygera at the weekend means Kelly could return to action next week. He is looking at a longer run in the Fulham side when this week's international business is taken care of, and is optimistic about the future.
At least this season's experiences can only help for his next two games for his country.
Kelly added: 'I don't get too chances to play against English players too often but Europe has been great and it gives you a great boost for these games and gives you an insight into these teams and what these players are like and how they set up against you.
'It's been a frustrating season. I have been sort of rambling through the games and performing so I feel good, I feel fit and I am really looking forward to these games.
Team players: Kelly and Duff in action with west London club Fulham
'It's all that Damien and myself can talk about in the last few weeks. We have been saying basically how big the games are and how much is riding on them.
They are so important and obviously we have not achieved anything yet. We have had a good campaign and got ourselves into a good position and can qualify.
'It would be such a shame to let all that hard work and effort go to waste. So we are very determined as a team and everybody can see the close knit unit that we are.
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