Newcastle started with an aggressive press but were quickly picked apart by a Brighton team keen to reassert themselves after a 3-1 loss at home to West Ham United last week.
They took the lead when Newcastle goalkeeper Nick Pope messed up a clearance and, though he saved a shot from a tight angle by Kaoru Mitoma with his foot, could not hold Billy Gilmour’s pile-driver shortly afterwards.
The rebound fell to 18-year-old Ferguson who rifled home from the edge of the six-yard box.
Newcastle’s evening was summed up in the 54th minute when Kieran Trippier under-hit a pass a few metres in front of his own goal and the defender breathed a sigh of relief when striker Brighton’s Joao Pedro wasted the opportunity.
Their luck was not to last though and Ferguson doubled Brighton’s lead in the 65th when he was left unmarked and advanced before curling home an exquisite shot from distance.
The visitors still did not learn their lesson and Ferguson completed his hat-trick with a strike that deflected off Magpies defender Fabian Schar five minutes later.
“It is hard to take in, as a kid you want to score as many goals in the Premier League, so when you score a hat-trick it is a good day,” a delighted Ferguson told Sky Sports in a post-match interview.
Newcastle managed only one shot on target before Callum Wilson netted their consolation goal two minutes into second-half stoppage time and they could have conceded a fourth but Mitoma missed the ball with the goal at his mercy.
The win moves Brighton up to fourth on nine points from four games, three off leaders Manchester City and one behind Tottenham Hotspur and West Ham.
“It (the result) is good, bad result last week and we needed to bounce back. We came out flying this week and we got that good luck in the end,” Ferguson said.
Newcastle’s third straight defeat leaves them in 14th spot on three points.
“I think the 3-1 scoreline is damaging for us but I didn’t think it reflected the whole game,” Newcastle coach Eddie Howe told Sky Sports.
“We tried to impose ourselves on them, but they’re a very good possession team and they started to control the game with the ball … but we still had our moments.”
(Reporting by Philip O’Connor, editing by Pritha Sarkar and Ken Ferris)