Tunisia stretched their unbeaten run in Africa Cup of Nations openers to eight matches as they were held to a 1-1 draw by Cape Verde at the Estadio de Ebebiyin in Ebebiyin.
George Leekens' men took a deserved lead on 70 minutes when Mohamed Ali Moncer rounded off a superb team move with a sidefooted finish into the roof of the net.
However 2013 quarter-finalists Cape Verde demonstrated their resolve and they levelled proceedings seven minutes later as Heldon converted from the penalty spot to salvage a point.
Earlier in the day, DR Congo and Zambia shared the spoils with the same scoreline as Crystal Palace winger Yannick Bolasie cancelled out Given Singuluma's quick-fire opener.
The results leave all four sides on one point going into the next round of matches.
After the two games the previous day had passed with little trouble, the Group B opener was slightly marred by a small number of supporters clashing with the large police presence outside the stadium after fans had to be turned away as the ground had reached its relatively low capacity of 5,000.
There were also heavy delays before kick-off as fans with tickets waited for everyone passing through the turnstiles to be screened for Ebola.
On the pitch, Zambia made a blistering start and they took an early lead after just 62 seconds in front of a half-empty stadium owing to the increased security measures.
Congo 'keeper Robert Kidiaba punched a cross clear and it fell to Singuluma, who lashed home an arrowed strike from the edge of the area.
That set the tone for an open game but it took Congo until six minutes after the hour mark to restore parity, and it came via Bolasie's well-hit strike into the bottom corner as both teams settled for a draw.
Neither side could manage to claim a victory in the later match in the group between Tunisia and Cape Verde in a game that didn't really get going until 20 minutes from time.
A beautifully weighted pass by Jamel Saihi fed the overlapping Ali Maaloul and he delivered a tempting cross that was converted at the far post by Ali Moncer.
However, Cape Verde, who perhaps should have been ahead long before they fell behind, remained undeterred and they found an equaliser on 77 minutes.
Striker Heldon exhibited his lightning pace which drew a foul from Syam Ben Youssef in the area, and he dusted himself down before sweeping the resulting penalty into the top corner.
The tournament, held in Equitorial Guinea after original hosts Morocco pulled out over Ebola fears, continues tomorrow as Ghana face Senegal while Algeria entertain South Africa.
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