A Celtic collision course has been set for Cardiff on Monday, but Wales and Ireland must negotiate Friday's World Cup qualifiers against Georgia and Moldova, respectively, to set up an encounter of winner takes all.
If Ireland slips up, victory in Tbilisi, Georgia, in a game played prior to the kickoff in Dublin would be enough for Wales to secure second spot behind leaders Serbia, currently four points clear in Group D. Ireland probably need to win both of their remaining matches since four points (or six for that matter) may not prevent them from becoming the worst-performing second-place team in UEFA qualifying.
Only eight of the nine second-place teams go through to November's playoffs, and since results gained against the bottom-ranked sides in each group don't count toward totals, it may take until full-time in Tuesday's set of qualifiers to work out who progresses.
Those are the rather complicated mathematics at hand, but there are plenty more strands to consider. Bale's injured calf robs Wales of one of the world's best players, without whom manager Chris Coleman's team have not won a match since 2013, drawing three and losing three.
The Irish will also be without their own leader. Captain Seamus Coleman may be back in Everton training but is still yet to play a minute of competitive football since having his leg shattered by Wales' Neil Taylor when the teams played out a 0-0 draw in March.
The aftershocks of that night in Dublin, bad-tempered long before Taylor's wild challenge, make Monday something of a grudge match. Bale's absence received little sympathy from Ireland assistant manager Roy Keane. "He is obviously an important player for them but we are missing Seamus Coleman and Jon Walters," Keane said on Tuesday. "They are as important to us as Bale is to Wales so that is life."
Bale's absence against Ireland was zero cause for celebration for one of football's most taciturn operators. "This idea of a buzz and that we were going around knocking each other's doors and hugging each other?," Keane scoffed. "I always think that if you want players to be missing in public then you are being very disrespectful to other players."
Both Keane and manager Martin O'Neill instead spoke of the need to concentrate on Moldova before crossing the Irish Sea for Monday's match. Burnley forward Walters is missing with a knee problem, robbing Ireland of someone who has become more important to his international team than his club sides. It was Walters' two goals in a playoff with Bosnia and Herzegovina that booked Ireland a place at Euro 2016.
Like semifinalists Wales, Ireland, who gave hosts France an almighty scare before eventually losing 2-1 in the last-16, have found it tough to recreate the buzz of last summer. World Cup qualifying, a tougher discipline than the Euros, has been a grind. Two-year extensions for O'Neill and Keane were announced on Thursday, but they have come under criticism for their team's squandering of a strong position gained by a creditable 2-2 draw in Serbia, a 1-0 home defeat of Georgia and away wins in Moldova (3-1) and Austria (1-0).
Three successive draws, with that Wales stalemate preceding a 1-1 draw with Austria which required a late Walters leveller and the same scoreline in Georgia let Wales back in when the magic that fired them to great things in France has been evading them.
"This campaign we haven't always had Bale, Aaron Ramsey or Joe Allen," explained Coleman on Wednesday. "They are obviously three super-special players and we haven't always had them, but the lads who have come in have been absolutely magnificent."
With Bale struggling to be ready for November's playoffs, Wales may look to a young man who might one day succeed the Real Madrid man as his country's talisman. Liverpool's Ben Woodburn is just 17, but his wondrous 25-yard goal in last month's 1-0 defeat of Austria revived Wales' qualifying campaign, and it may be time for Coleman to play a joker in someone of school age who has played just 44 minutes of senior club football this season.
"He reminds me of what Gareth was like when he was younger," midfielder David Edwards said.
Little love will be lost on Monday, but both Wales and Ireland have suffered problems the other might empathise with.