An own-goal in extra time sends Senegal into the AFCON final and keeps them on course for their first title.
Both sides miss second-half penalties before a goalie error gives the Lions of Teranga victory.
This semi-final match began with a number of stoppages before Senegal started to gain control led by their Liverpool star Sadio Mane.
His skill created chances and though none were taken it seemed the west Africans would get the upper hand.
They also went close through a great effort by full-back Sabaly.
Tunisia were left with some threats from set-plays.
But in the second half it could have been much different as striker Khenssi had two makeable chances.
The first he chipped too high and the second was well stifled by goalie Gomis.
Then two penalties were awarded.
A Sassi shot was adjudged to have been handled and the same man stepped up to take the spot-kick.
Sadly his weak effort was easily saved.
Soon after Senegal had their opportunity but Saivet's shot, though more decisive, was well saved by Hassen.
And so we moved into extra time with the match goalless and neither side dominating.
The deciding moment would come in the 100th minute when a right-wing corner was misjudged by Hassen and the ball went in off the hapless Bronn.
It was a cruel blow for the Tunisians (who had often been driven on by St Etienne's Khazri)
A possible late lifeline for the Carthage Eagles came after the Ethiopian referee awarded another penalty.
But the intervention of VAR resulted in that decision being reversed much to the delight of the Senegalese.
And in the end, it was a single goal win for the Lions of Teranga who remained on course for a maiden AFCON triumph.
report & analysis - John Bethell