Eriksen collected a pass from Dele Alli and drilled a low shot into the corner with just two minutes of normal time remaining.
It had looked as though Spurs would be frustrated as Seagulls goalkeeper Mat Ryan and central defenders Shane Duffy and Lewis Dunk produced superb performances to keep them at bay.
But Eriksen's goal means Brighton remain only three points clear of third-from-bottom Cardiff City with three matches left each.
Spurs: 27 Apr v West Ham (H)
Brighton: 27 Apr v Newcastle (H)