The delighted Italian saw his side surge into a 2-0 lead at St James' Park with barely five minutes on the clock, but then have to survive a concerted fightback as Andy Carroll led an onslaught.
City climbed into second place in the Barclays Premier League table, two points behind arch-rivals Manchester United having played two more games, as a result, although Mancini is not getting carried away just yet.
He said: "I like Boxing Day. Last year, we won; this year, we won.
"I am happy with this first year, but it is my opinion that we need to improve again, we need to work. Only if we do that can we arrive at the top and win something at the end of the season."
Asked to some up his first year in charge at Eastlands, Mancini added: "Fantastic because the Barclays Premier League is the best league at this moment in Europe and for me, it is an incredible experience."