A Tuisila Kisinda goal six minutes from time condemned record eight-time champions Ahly to a 1-0 Group D defeat by V Club of the Democratic Republic of Congo in Kinshasa.
Burkina Faso-born Amed Toure bagged a second-half brace for ASEC Mimosas of the Ivory Coast to deliver a 2-0 Group A win over twice champions Wydad in Abidjan.
By winning, 1973 African champions V Club joined Ahly on seven points with the Egyptians clinging to first place on head-to-head records having won the first meeting 2-0.
JS Saoura of Algeria host Simba SC of Tanzania later Saturday in Bechar and a win for either club would lift them to the top of the standings with one round remaining.
While Ahly are chasing a ninth title and V Club a second, Saoura and Simba hope to reach the quarter-finals of the elite African club competition for the first time.
The heroics of goalkeepers Nelson Lukong, a 38-year-old Cameroonian, for V Club and Mohamed el Shenawy for Ahly kept the Kinshasa clash goalless until six minutes from time.
V Club came closest to breaking the deadlock during the first half with a header from leading scorer Jean-Marc Makusu Mundele rebounding off the post.
Lukong was at his most agile early in the second half to deny Nasser Maher, Nigerian Junior Ajayi and Karim 'Nedved' Walid in quick succession.
El Shenawy was equally impressive midway through the second half to foil Ngonda Muzinga, whose close-range shot after a Kisinda back-heel appeared goal bound.
The match winner had an element of luck as 19-year-old Kisinda scored his first goal of the Champions League campaign via a deflected shot.
Toure, who was born in Ouagadougou and has Burkinabe and Ivorian nationality, ended a five-match goal drought by constantly threatening 2017 champions Wydad in the second half.
The 31-year-old striker broke the deadlock on 68 minutes and put the result beyond doubt with his second goal two minutes from time.
Toure last scored for 1998 African champions ASEC in a qualifying victory over Stade Malien of Mali in Bamako last December.
ASEC have seven points, the same number as Wydad and Mamelodi Sundowns of South Africa, who host bottom club Lobi Stars of Nigeria later Saturday near Pretoria.