The players appeared alongside each other at Scottish side Hamilton before moving to the Latics, with McCarthy joining in 2009 and McArthur the following year.
|17/2||James McCarthy is 17/2 with Bet365 to score anytime in Ireland v Germany
"I felt he played his best game of the season at Sunderland a couple of weeks ago [in a 1-0 defeat] and he was fantastic again against Everton," McArthur told reporters.
"He's gone from strength to strength this season and having known him for a long time and through working with him every day, I think he'll only get better.
"He's got a big role for his country [Republic of Ireland] now too and, hopefully like the rest of us he can impress for his national team and return injury-free for the next league match against Swansea City."
Wigan currently sit in 15th spot in the Premier League table after taking five points from their opening seven matches of the season.