Jacob Mulenga put the Copper Bullets into an early lead only for Zouhaier Dhaouadhi to level for the north Africans before the break. Given the spate of upsets Angola 2010 has already produced - Cameroon were turned over by minnows Gabon earlier in Lubango - it came as no surprise to see the Carthage Eagles being outplayed by Zambia for much of the match.
They went into a 19th minute lead when James Chamanga, who plays his club football in China, charged down the centre and found Mulenga on his right. The Utrecht midfielder controlled the ball well, fighting off Tunisia defender Ammar Jemal to slot an angled shot past goalkeeper Aymen Mathlouthi who should have done better. Zambia coach Herve Renard, Claude Le Roy's assistant with Ghana in 2008, justifiably raised his arms in delight.
Zambia were worthy of the lead after almost constant pressure up to this point, and they continued to bely their underdog status with forays into Tunisian territory. On a rare early incursion up the other end of the pitch skipper Karim Haggui, the lone survivor from the 2004 title-winning squad, hit over the bar.
Zambia, with skipper Christopher Katongo joined in midfield by his younger brother Felix, were proving a real handful for Faouzi Benzarti's north Africans, with only the back of a red shirt stopping Rainford Kalaba's close range thunderbolt after the half-hour mark. Tunisia were back on level terms though on 40 minutes when teenage striker Youssef Msakni tore the Zambian defence apart down the left, cutting the ball back to Dhaouadhi who slammed it into the roof of the net.
The two sides, both making their 14th appearance in this continental championship, emerged for the second half with everything to play for after Gabon's shock win over Cameroon earlier which split the group wide open.
Zambia appeared the more likely to regain the advantage, harrying the Tunisian backline seemingly at will. Benzarti took off Ousama Darragi on the hour and sent on Lens attacker Issam Jemaa in a bid to reinforce his goal scoring options against a side that had only mustered a paltry four goals in 10 qualifying ties.
Mulenga almost got his and his country's second goal in the 82nd minute when he unleashed a powerful climbing shot which thudded into the side netting. Maccabi Tel Aviv forward Emmanuel Mayuka did score seconds later but his effort was ruled offside. In injury time Mathlouthi could only punch Kalaba's powerful 22m freekick away to retain the status quo.
"This was two points lost," said the youngest of the five French coaches in the competition. "We started well but after the goal we didn't show enough discipline." His Tunisian counterpart, Faouzi Benzarti commented: "We could have won the game with our second half performance...but the draw is fair."