Spurs appeared to be heading for an underwhelming draw that would have seen Brighton edge closer to securing their Premier League safety, but Eriksen struck two minutes from time to cruelly deny Chris Hughton's hard-working side.
After a quiet opening, the first half grew into a lively encounter, with Spurs going closest just before the interval when Dele Alli had an effort blocked on the line.
Spurs stepped things up a notch in the second half but looked to have run out of ideas after Toby Alderweireld hit the post, only for Eriksen to eventually find the net late on, taking Mauricio Pochettino's men four points clear of fifth-placed Arsenal.
Precious little occurred during the early exchanges until Victor Wanyama's wild clearance went just over his own goal following a free-kick in the 14th minute.
Spurs livened up soon after and went close to the opener – Lucas Moura collected Eriksen's exquisite pass and played the ball across the face of goal, but Lewis Dunk brilliantly intercepted before Dele Alli could tap in.
Brighton were fortunate again a few moments before half-time – Shane Duffy crucially clearing Alli's close-range effort off the line.
Spurs dominated thereafter, but they struggled to break down Brighton's compact defence – Danny Rose's 25-yard strike testing Mat Ryan, before Alderweireld struck the right-hand post 18 minutes from the end.
Vincent Janssen was introduced for his first Premier League appearance since August 2017 as Spurs ran out of ideas.
But finally their persistence paid off, as Eriksen's left-footed drive found the bottom-right corner from 30 yards to continue Spurs' unblemished start at their new home and keep Brighton looking over their shoulder at Cardiff City in the relegation battle.
Spurs in the driving seat
With all of the candidates for the remaining top-four places dropping points in their last fixtures, it almost seemed as though none of them want Champions League football next season.
Consistency has been hard to come by all for all of them, so a win for Spurs could prove to be massive in the long run, particularly with Chelsea and Manchester United set to face each other at the weekend.
Eriksen elevates Spurs
Match-winner Eriksen had looked like Spurs' most likely route to goal throughout, with the Dane pulling the strings from midfield and going fairly close with a couple of long-range efforts. He eventually found the target and just in time, continuing his fine run of form.
