The game finished 31-20 after Kingston came back from two scores down in the first half, their iron defence preventing BNU scoring a single point in the second.
After going into break with a 20-14 lead, the visiting Buccaneers soon lost their momentum in the third quarter.
“The defence really stepped up to the game in the second half and didn’t let BNU gain a single yard, ” said Wasilij Korotchenko, president and defensive captain of the Kingston Cougars.
“That’s really good considering they scored 20 on us in the first half.”
The Cougars, who became an official team only in September, eased through their first two games against OBU Panthers and Imperial Immortals and Sunday’s win against the Buccaneers made it three out of three.
Mr Korotchenko said he had felt confident before the game:
“We go into every game with a mindset that we’re going to win.”
Offensive captain James Cherry said afterwards: “There was a lot of speculation within our division that we were going to get our teeth smashed in but we have now sent a statement to the league.”
He added: “BNU is a very good established team and we still managed to beat them.”
Over 100 people came to watch the Cougars’ home debut at Tolworth Court Sports Ground.
The Cougars’ next game will be played against Oxford University’s Cavaliers on February 12.