Tunisia beat Zambia 2-1 to dent Honour Janza's 2015 AFCON quarterfinal dreams.
The defeat ended Zambia's unbeaten run at the Africa Cup stretching back to 2012 when they were crowned champions.
Zambia's last defeat prior to Thursday came in 2010 when they lost to Nigeria in the quarterfinals.
All three goals came in the last 30 minutes of the second half after Zambia dominated the first half.
Emmanuel Mayuka put Zambia while Ahmed Akaichi equalised for Tunisia before and Yasine Chikhaoui snatched a dramatic late winner.
Zambia could have killed the game in the first half but were guilty of poor finishing.
Kalaba had two great chances going wide in the 15th and 22nd minutes as he terrorised Tunisian goalkeeper Aymen Mathlouthi throughout the first half.
However it was Mayuka who had the better chances.
His 40th minute header was saved by Mathlouthi and four minutes later the Southampton striker fluffed from close range before the Tunisia goalkeeper saved the day.
Mayuka made up for his first half misses when he cracked in a shot off a cheeky pass from Kalaba in the 59th minute.
But Zambia's celebrations were shortlived and Tunisia hit back seven minutes later when Ahmed Akaichi tapped in a Mohamed Ali Moncer corner.
Zambia’s woes were compounded in the 72nd minute when Mayuka was stretched off with an injury.
Mayuka's departure also saw Zambia's dominance fade and they were punished by Tunisia in the in the 88th minute when Yasine Chikhaoui headed in Hamza Younes cross.
Zambia slip to the bottom of Group B on one point and must now beat Cape Verde in their last game on January 26 to keep their hopes alive.
Tunisia, on four points, take on DR Congo on the same date in Bata.