The Republic of Ireland and Wales go head-to-head in Dublin on Friday night in a game which could prove pivotal to their respective hopes of making it to the 2018 World Cup finals in Russia.
Here, Press Association Sport takes a look at some of the talking points surrounding the game.
Martin O'Neill could be forgiven for cursing his luck after seeing player after player ruled out of his plans by injury and suspension. Already missing star man Robbie Brady as a result of his second yellow card of the competition in Austria, O'Neill has since has to scratch the names of Shane Duffy, Ciaran Clark, Harry Arter, Wes Hoolahan and Daryl Murphy from his list, all of whom might have played a significant part against the Welsh.
The loss of Brady, who has played in both midfield and at left-back for his country in recent times, and Hoolahan in particular has left O'Neill with a major gap to plug. The kind of invention they contribute will be difficult to replicate, and he will hope the likes of Jeff Hendrick, James McClean and Aiden McGeady can provide the spark Ireland will need to prosper.
Gareth Bale has been Wales' talisman during their rise to prominence in recent seasons and his return to fitness after an ankle injury represents a massive boost for manager Chris Coleman and quite the reverse for O'Neill. The Real Madrid star is unlikely to be fazed by Ireland assistant manager Roy Keane's tongue-in-cheek assertion that the only way to stop him is to "hit him...fairly", but the extent to which he is allowed to dictate the game could go a long way towards determining the outcome.
Aaron Ramsey was the toast of the Welsh nation as he turned in a series of stunning individual displays at the Euro 2016 finals in France to help his country reach the last four. However, injuries and patchy form for club Arsenal since have taken their toll and - having missed the first three qualifiers - he will be desperate to make up for lost time.
Wales captured the imagination of the neutrals as well as their own supporters as they surged unheralded into the semi-finals last summer before losing 2-0 to eventual winners Portugal. However, they have won only one of their first four games in the new campaign and while they are unbeaten to date, they trail Group D leaders Ireland by four points and another positive result for O'Neill's men could prove hugely significant in how the campaigns eventually pans out.