By Nick SaidEquatorial Guinea received a soft penalty in the dying seconds of normal time before Javier Bilbao netted a superb winner to seal a historic semi-final place for the African Nations Cup hosts following a 2-1 extra-time victory over Tunisia in Bata on Saturday.
The north Africans appeared to be on their way to the last four when Ahmed Akaichi put them ahead with 20 minutes to go.
But with just seconds remaining of normal time, Mauritius referee Rajindraparsad Seechurn handed the home side a dubious penalty that was converted by Bilabo, who later grabbed the winner with a magnificent free-kick.
It left Tunisia seething, and there were at times ugly scenes as tempers flared and Seechurn battled at times to contain the emotions.
The manner of the win will be debated long and hard, certainly Equatorial Guinea benefitted from a soft penalty, but by that time the Tunisians could be accused feigning injury and time-wasting as they tried to wile down the clock.
Equatorial Guinea will now play the winner of Sunday's quarter-final between Guinea and Ghana, with that semi-final fixture to be played on Thursday in Malabo.
Tunisia were almost gifted an opener when home goalkeeper Felipe Ovono dropped a ball into the box, but re-gathered just in time with Wahbi Khazri about to pounce.
Equatorial Guinea's best chance of the opening half also came from some uncertain goalkeeping as Aymen Mathlouthi also spilled the ball, but Bilboa's goal-bound shot was blocked by Syam Ben Youssef.
Ovono made a superb save to deny Akaichi after the forward was teed-up by Yassine Chikhaoui as Tunisia made a fast start to the second half, but chances continued to be few and far between.
Akaichi finally broke the deadlock 20 minutes from the end when he profited from a good cross by Hamza Mathlouthi to fire into the Equatorial Guinea net.
The home side had a great chance to equalise in the closing stages when Iban Edu found Emilio Nsue, but the star man saw his shot saved by Tunisian keeper Mathlouthi.
Then came what could yet be the pivotal moment in the competition.
Edu tumbled to the ground in the penalty-box after what appeared to be minimal contact from Tunisian defender Hamza Matlhouthi and Seechurn pointed to the spot.
It took a while for the referee to calm the Tunisia protests, but when he did, Bilboa stepped up and coolly slotted home the spot-kick.
It was clear that Tunisia were rattled and they battled to reorganise themselves for the extra-time period.
Again it was Bilbao who provided the decisive moment though as he curled home a 30-yard free-kick that proved a worthy winner of any match, to send the home fans into complete rapture.
Equatorial Guinea are into the last four of the continental championship for the first time in their history, bettering the quarter-final finish they managed when they co-hosted the finals with Gabon in 2012.