Glenn Murray opened the scoring in the second minute with his 20th league goal of the season, before Tomer Hemed and Uwe Huenemeier added further goals soon after the break.
Brighton have 83 points and stand two points in front of Newcastle, who host Burton Albion on Wednesday, and 10 ahead of third-placed Reading, who beat visiting Blackburn Rovers 3-1.
Leeds United, fifth on 69 points, suffered a second straight loss with a 2-0 reverse at Brentford, while Sheffield Wednesday won 2-0 at Rotherham United to climb two points above Fulham, who lost 4-2 at Derby County, into sixth spot on 66.
Fourth-placed Huddersfield Town, who have 71 points, welcome Norwich City on Wednesday.
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The top two in the second-tier are promoted to the Premier League while those placed third to sixth go into the playoffs.
(Reporting by Tom Hayward; Editing by Ken Ferris)
