Injury-hit Sunderland would be without three players for the January tournament and more than three months before AFCON had even kicked off, it was causing concern.
Moyes knew a tough month lay in store and so it proved with the best centre-back Lamine Kone representing Ivory Coast, record signing Didier Ndong Gabon and Wahbi Khazri Tunisia.
The turn of the year started well enough, with Sunderland holding Liverpool to a draw and it ended in a similar fashion; with Tottenham Hotspur leaving Wearside with just a point.
Results and performances in between were desperate, with Burnley knocking Sunderland out of the FA Cup and morale-sapping defeats to Stoke City and West Bromwich Albion.
Winger Khazri wasn’t a huge miss given he had barely featured since Moyes took charge but he was another body, another option Moyes couldn’t call upon.
Kone and Ndong’s absence did hurt Sunderland, even though neither had been in sparking form before they left.
They were still key first team regulars and with a crippling injury list, their absence was felt, with Moyes fleshing his bench out with youngsters.
Yet, while the tournament was an unwanted short-term headache, Sunderland look set to benefit long-term – with both Kone and Ndong coming back refreshed, revitalised and raring to go.
Both have come back on top form, Kone refreshed having been away but not actually getting any game time for the Ivory Coast during the tournament.
Ndong played all three group games before Gabon’s exit and he seems to have played himself into form, with the 22-year-old impressing against Spurs and starring against Palace.
Sunderland fans had seen little in the way of attacking threat from Ndong since he arrived for £13.6million from Lorient.
The 22-year-old changed all that at Selhurst Park, firing home from 25-yards after dispossessing Joe Ledley who hesitated for a nano-second.
A brilliant individual goal from Ndong, who visibly grew in confidence. A moment for him and the jubilant travelling support to treasure.
Kone has been immense at the back, Christian Benteke didn’t have a sniff on Saturday, with the powerful centre-back returning to his commanding best.
With Jordan Pickford back in full training and breathing down Vito Mannone’s neck, the spine of Sunderland’s team is looking far stronger.
Sometimes a change of scenery can be as good as a rest and both Kone and Ndong are better for their spell away at the Africa Cup of Nations.
“A lot of the boys have come back for the better, they look a bit fresher,” said Moyes.
“We’ve needed them back as well. It is a very big boost. They both played against Spurs and were brilliant then.
“Lamine Kone has done really well and he played very well at Palace.
“Didier Ndong, he is young and sometimes we expect too much of him, but he scored a great goal. He has great energy.
“He is still learning the language and the culture, but Didier did really well. We missed them both in January, really missed them.”
A break from the pressure cooker of the Premier League has done them the world of good, with Sunderland now better for it.
Their return to form is timely and much-needed.