With Bale out of the team, the Dragons are a side unable to reach major tournaments, just as they now have done following the Republic of Ireland's determined and disciplined 1-0 win in Cardiff.
Wales boss Chris Coleman made only one change to the side which won 1-0 in Georgia on Friday evening with Hal Robson-Kanu replacing Sam Vokes up front for the crunch Group D clash. With Robbie Brady and James McClean back from suspension, both players were restored to the team. Serbia have booked a top-two finish - and a victory in their home game with Georgia will guarantee their place in Russian Federation.
The Irish, who can secure second spot in Group D and a playoff spot with victory over Wales, must cope without the 30-year-old Long, who played against Moldova on Friday and has won more than 70 global caps.
That dream looked over last month after the defeat to Serbia left Ireland needing to win their two November games and hope that results in other groups fell their way.
Duffy played a key role for the Republic on Friday night, playing his part in the opening goal for Daryl Murphy after just two minutes.
Ireland punished Wales' shortcomings in the final third when Hennessey's distribution put Ashley Williams under pressure and he was dispossessed by Hendrick.
In that unlikely scenario, the playoff spot would, believe or not, go to the team who lead on fair play points.
A win guarantees second place in the group and a place in the play-offs.
'But if we keep doing what we've been doing, it will give us a chance of having a good night [tonight].' Coleman has dismissed talk of a grudge match after what happened when the sides met in March.
The 28-year-old said: "It's a sticky one because in the press, you're talking about the Wales game and everybody expects us to walk over Moldova".
"All I can control is my own group, the players and my staff - that's what I concentrate on and that's what we'll do in this game", said Coleman.
Wales are slight favourites for the win with the draw priced at 2/1. He has 26 goals in 68 worldwide appearances, including key strikes against Georgia and Serbia in the current campaign which should have put Wales on the road to Russian Federation. "I felt it was always going to be like this".