The Republic of Ireland star featured for his country in both the 6-1 thrashing at the hands of Germany last Friday and the 4-1 victory over the Faroe Islands on Tuesday.
And, ahead of a return to club football against Swansea City this weekend, McCarthy wants the Latics to find their "rhythm" as soon as possible.
"It’s good to be back and I’m really looking forward to the game tomorrow," McCarthy told the club's official website. "We’ll go there looking for all three points but obviously it is going to be a difficult game.
|7/4||Wigan are 7/4 to be relegated from the Premier League with Bet365|
Despite Michael Laudrup's side being in the midst of a poor run, and with rumours gathering pace of unrest at the club, McCarthy insists Wigan will be taking nothing for granted.
"A game against Swansea is always going to be difficult much like every game in this league," he continued.
"We’ll go there and give it our best shot and we certainly won’t be going to the game taking it lightly because they have got great quality in their squad.
"If we can keep building up the points then we can kick on from that momentum."