Aristide Bance came off the bench to fire Burkina Faso past Tunisia and into the Africa Cup of Nations semi-finals.
It appeared as though the first last-eight tie was headed for extra-time as the two sides struggled to assert dominance in Libreville.
But Bance, who had only been on the pitch for four minutes, ensured that the additional period was not required when he drilled home after quick thinking with Bertrand Traore at a free-kick with 10 minutes remaining.
And the match was put beyond doubt when the dangerous Prejuce Nakoulma scored a second on the break in the closing stages.
Burkina Faso boss Paulo Duarte may feel the result was justified on the balance of play with Nakoulma wasteful in the first half, while Traore and Bance both hit the woodwork.
For Tunisia boss Henryk Kasperczak there will be a sense of deja vu, with the Pole also in charge of Tunisia when they were beaten by Burkina Faso at the same stage of the 1998 AFCON.
Taha Yassine Khenissi's physical presence caused problems for the Burkina Faso defence early on and he twice saw headers clear the crossbar.
Burkina Faso created the better openings, though, and Nakoulma wastefully lashed an effort over the top after racing onto Traore's throughball.
Shortly after, Nakoulma showed quick feet to dance into the area and he combined with Hamdi Naguez to set up Traore, whose lofted shot bounced off the crossbar.
Those misses almost proved costly when Mohamed Amine Ben Amor curled a 25-yard effort narrowly wide of the left-hand post.
Tunisia went even closer in the 33rd minute as Khenissi got the near-post flick on a Naim Sliti corner and both Aymen Abdennour and Mohamed Ali Yacoubi agonisingly failed to apply the finishing touch.
Early in the second half, Khenissi powered a header straight at Kouakou Herve Koffi after shrugging off his marker to meet Youssef Msakni's deep cross.
Burkina Faso began to enjoy a spell of pressure and Charles Kabore's cross was headed wide by Bakary Kone, who perhaps should have let the ball run for centre-back partner Steeve Yago.
Wahbi Khazri made little impact on the game for Tunisia before being hauled off on the hour and the Sunderland forward seemingly refused to shake Kasperczak's hand on his way off the pitch.
And the mood did not improve for Tunisia in the 80th minute. Traore pretended to still be in discussion with Bance before laying off the free-kick to his team-mate, whose low 20-yard shot nestled in the right-hand corner.
Bance hit the post and Nakoulma saw a shot cleared off the line as Burkina Faso sought a second, which duly arrived when Nakoulma raced clear on the counter and rounded Koffi - who had rushed off his line - 40 yards out before rolling into the unguarded goal.