The Irishman heralded his manager's contribution to the Latics' shock success as he declared the victory an "unbelievable achievement" and a "dream come true"
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McCarthy, who started the final and has been ever-present for Wigan in the league this season, was effusive in his praise of Martinez, proclaiming it an "honour" to even work with the Spaniard.
"I think the gaffer is a tactical genius; he's brilliant. I've been here for a couple of years and I've learned so much underneath him," he told ESPN.
"It's a real honour to work underneath him. Really, it's down to his tactics that we came away with the cup."
The 22-year-old, who moved to Wigan from Hamilton in 2009 and is now being targeted by some of the biggest teams in the country, went on to admit that the FA Cup success was "unbelievable" and something he had dreamt of as a child.
"No, it's unbelievable, it's an unbelievable achievement. Look at the fans, look at what it means to the club," he continued.
"I'm speechless to be honest, it's a dream come true - what you dream of as a kid."