England, Scotland, Wales, Northern Ireland and Republic of Ireland kick off their World Cup campaigns this weekend.
Sky Sports pundit Charlie Nicholas is expecting tough tests of each nation's credentials as England travel to Slovakia, Scotland head to Malta, Wales host Moldova, Northern Ireland visit Czech Republic and Republic of Ireland face Serbia.
You can follow the action on Sky Sports over the next few days and here's what the former Scotland forward is backing in his Sky Bet tips...
Slovakia v England
I don't think there's much excitement around Big Sam's arrival and it's going to be a challenge for him working with the big names. I know he's had Jay Jay Okocha etc. but this first get-together is going to be a tough one, trying to figure out the characters.
However, I think there will still be a strong adrenaline among the players to impress. The fact that he's dropped Jack Wilshere and called up Danny Drinkwater epitomises what he'll try to build, picking players on performances rather than reputations.
It might not be pretty at first but I still expect England to be organised and I think they'll get the job done, with Allardyce doing a better job in utilising Harry Kane and hopefully Jamie Vardy from the bench.
Charlie predicts: 0-2 and Kane and Vardy both to score (50/1 with Sky Bet)
Czech Republic v Northern Ireland
This Northern Ireland team will come back together and be wondering how what they achieved in France actually happened.
There is a bit extra pressure on them now and it will be interesting to see how that impacts the way they play. Their quality was mainly in midfield and defence as the quality of their forwards was exposed a bit so they need to bounce back.
It obviously wasn't a good tournament for the Czechs so it looks like they're having a fresh start for the new campaign and they'll be demanding a response.
Charlie predicts: 2-0 and Vaclav Kadlec to score first (20/1 with Sky Bet)
Malta v Scotland
This is a really dangerous game for me. I'm not feeling upbeat about my national team right now.
We've got Leigh Griffiths out, who is the only player scoring goals right now, so the other player we'll be relying on is Robert Snodgrass.
It was a really flat end to the Euros qualifiers and I'm not sure Gordon Strachan is convinced by what he's got.
Malta got a pretty decent draw at Estonia so certainly won't roll over and with a lack of goals we fall back into the category of being well organised and hard to beat. I'm not a fan of that, so we're resting everything on Snodgrass delivering.
Malta 1-2 Scotland and Snodgrass to score first (25/1 with Sky Bet)
Serbia v Republic of Ireland
Serbia are always dangerous at home. They've got some quality players and Ireland know they will probably need a result here if they're to have a chance of topping the group.
I don't think the departure of Robbie Keane will hit them too hard in terms of their chances, with the likes of Shane Long overtaking him in the pecking order.
My concern is whether they'll have the defensive discipline to grind out a result in Serbia.
Charlie predicts: 2-0 and Zoran Tosic to score first (30/1 with Sky Bet)
Wales v Moldova
I like what Chris Coleman has done since Euro 2016. He's shown his commitment and brought his good mate Kit Symons back in.
However, Aaron Ramsey is out and the last time he didn't play they got knocked out of the Euros. He's almost as important as Gareth Bale.
Moldova will double up on Bale and assume that nobody else will be able to trouble them, but I fancy Hal Robson-Kanu to be to impress after securing his move to West Brom.
Charlie predicts: 1-0 and Robson-Kanu to score first (10/1 with Sky Bet)