Imed Meniaoui volleyed a 94th-minute winner as Club Africain came from behind to beat Group A leaders FUS Rabat of Morocco 2-1 in Rades on the outskirts of Tunis.
All eight Group A games have produced home wins so FUS, who lead on goal difference, Club Africain, Rivers United of Nigeria and KCCA of Uganda have six points after four rounds.
Al Hilal went top of Group C thanks to a 2-1 triumph over Smouha of Egypt in Obeid with Ghanaian Nelson Ladzagla snatching the winner four minutes into additional time.
A corner led to a goalmouth melee and the west African stabbed the ball past goalkeeper Mohamed Abou-Gabal into the corner of the net.
Abaker Girfa scored off a rebound on 72 minutes for Hilal and Islam Mohareb levelled five minutes from time with a fierce close-range shot.
Hilal have seven points, Recreativo Libolo of Angola and top seeds Zesco United of Zambia six and Smouha four with group winners and runners-up securing last-eight places.
Mouloudia Alger of Algeria, whose lone CAF title came 41 years ago, replaced record three-time Confederation Cup winners CS Sfaxien as leaders of Group B.
Clinical Hichem Nekkache bagged a brace inside 29 minutes as Mouloudia edged gutsy Mbabane Swallows of Swaziland 2-1 in Algiers.
Njabulo Ndlovu reduced the deficit with a superb long-range shot 17 minutes from time for the first club from the tiny southern African kingdom to reach the group phase.
Sfaxien slipped to second after drawing 1-1 away to bottom team Platinum Stars of South Africa in northwestern mining town Rustenburg.
Bongi Ntuli poked a cross into the net on 58 minutes for winless Platinum and Maher Hannachi levelled after 76 minutes through a side-foot shot off a cut-back.
Goalkeeper Mbongeni Mzimela, recallled after Stars conceded seven goals in their previous two group games, rescued his tiring team several times during a frenetic finish.
Horoya of Guinea lead Group D with eight points, SuperSport United of South Africa and title-holders TP Mazembe of the Democratic Republic of Congo have six, and Mounana of Gabon are pointless.