Brighton took advantage of a first-half capitulation by Leeds United at the Amex Stadium to move just two points behind Championship leaders Burnley.
Tomer Hemed opened the scoring with a chipped penalty, the hosts’ first goal of four inside the first 38 minutes.
An unfortunate own goal from Liam Cooper doubled Brighton’s lead, before Hemed slotted in his second and Lewis Dunk headed in from a corner.
The defeat was Leeds’ heaviest since Steve Evans took charge in October.
Evans was told not to speak to the media after the match by chairman Massimo Cellino, who left the ground at half-time.
Assistant boss Paul Raynor carried out the club’s post-match television obligation but did not speak to the rest of the media, including BBC Radio Leeds reporter Adam Pope.
A slightly improved second-half display, albeit with Brighton goalkeeper David Stockdale rarely called into action, did little to cheer the 1,522 travelling fans – many of whom had made a 520-mile round trip to Sussex.
The two teams appeared evenly matched until Leeds full-back Scott Wootton was adjudged to have fouled Liam Rosenior in the penalty area, and Israel international Hemed cheekily beat goalkeeper Marco Silvestri from 12 yards.
After that setback, Cooper’s deflection took Sam Baldock’s toe-poked effort into the net and the visitors fell apart defensively and were out of the contest by half-time.
Brighton began the match with an inferior goal difference compared to many of their promotion rivals, but were unable to stretch their lead further in the second period.
The Seagulls remain fourth in the table despite a second consecutive 4-0 victory, but they are now just a point behind second-placed Hull and have an 11-point cushion to Cardiff in seventh.
Brighton manager Chris Hughton told BBC Sussex:
“It was a very complete performance. At the moment we look like we can score goals, but in the last two games we’ve kept two clean sheets.
“It’s been a very good reaction to a disappointing defeat at Cardiff.
“We’re a side that generally haven’t been big goalscorers this season. We threatened in the first part of the season, when I thought some of our play was really good, but we didn’t have the goals to show for it. At the moment, we do.”
Leeds assistant coach Paul Raynor told Sky Sports:
“The first-half performance was shambolic. Our defending was atrocious and the manager is going to dissect it with the players.
“We only had 15 minutes at half-time to try to put a shape together and to show a bit of pride and commitment and heart out there and I felt we did that in the second half.
“But the first half was absolutely shambolic and it simply was not good enough.
“We can’t worry about the chairman. If I was him I would have gone as well to be fair, because he doesn’t want to see his football club playing like that and I don’t blame him for that.”