The diminutive winger struck with less than three minutes on the clock, slotting home after a neat team move to get the Magpies off to a dream start.
Yoan Gouffran doubled their lead on the stroke of half-time, before substitute Peter Whittingham reduced the arrears with a quarter of an hour remaining to set up a nervy finale.
However, United saw out the remaining minutes to register an eighth-straight win in all competitions, though Atsu admitted he and his teammates had been made to "work hard" for another three-point haul.
The Ghanaian felt the Magpies were good value for their latest victory, and spoke of his glee at opening his account in front of the Gallowgate faithful.
"I said I wanted to score at home, and I was very happy to celebrate my goal," he told nufc.co.uk. "The feeling was great. In the first-half, we played really well. We pressed them high, we created a lot of chances and we could have killed the game.
"But in football, it is not that easy. They scored one, and we then fought hard to keep it at 2-1. We know that no team in the Championship is easy, so we tried to work hard. We worked hard for 90 minutes and we deserved the win."
Prior to the Bluebirds' visit, Atsu had started just twice for United in the Championship - his only other goal coming on his first, away at Rotherham United last month.
He racked up almost 90 minutes against Neil Warnock's side, however, having come into the side to replace the suspended Matt Ritchie.
Atsu will now link up with his native Ghana for the Black Stars' World Cup qualifier against Egypt next week, the 24-year-old just a handful of caps away from his 50th for his country.
After signing off on a winning note, Atsu believes Newcastle can return from the international break full of confidence - and is hopeful of retaining his place in the side for their trip to Leeds United a fortnight tomorrow.
"We have the winning mentality, and everyone will take that with them going into the break," he said.
"We are in front (at the top of the table) now, but we know it is difficult. You can't predict any game. We need to keep fighting, keep working hard and keep that winning mentality. If we do, we will go far.
"I'm very happy that there is good competition in the team - it keeps us going. I will need to continue to work hard. Of course, I want to keep starting and helping the team."
