The victory marks a perfect start for the hosts, who were making their debut in the CHAN tournament.
The only goal of the match came on the stroke of halftime, through attacker Austin Odhiambo.
McCarthy was full of praise for his charges, applauding their commitment and tactical execution.
"First of all, I'm very proud of my team, many of them, it's the first time that they step out to such a big stage. So, the fact that they played against one of the tournament's favourites in my eyes, this is a team with so much experience, DRC, they've won this tournament twice, so they know what’s in the past, so they know what winning is about,” McCarthy said.
“They know what it is about playing in this tournament and for us who's very novice to this, the fact that we didn't let the nerves get the best of ourselves. At times, yes, we were nervous but once we settled down, I think we played some really good football against a team that's organised and well prepared. So, yeah, I was very proud of my players."
The victory gives Kenya a crucial three points in Group A, which also features top footballing countries with strong leagues like Morocco, Zambia and Angola.
Kenya’s next game will be against Angola, who also narrowly lost to the Atlas Lions 1-0 in the opening game at Nyayo Stadium, also in Nairobi.
McCarthy says they will take the positives from the opening game to their next match.
"The momentum shift and they're looking for an equaliser, they made five changes within the first 15, 20 minutes of the second half but we just tried to stay calm and not panic and not giveaway unnecessary fouls because they have such big number nine, big players, who are really very dominant,” he added.
“So, while we controlled those situations I think the game kind of planned out but at the end of the day, it was at times a little bit messy from us but you have to understand it's our first time for many of my players that they play under such pressure and in front of such a big, big crowd."