Lobi Stars won at home and CS Constantine grabbed a late away win in other matchday 1 clashes in the premier African club competition.
Anice Badri, seventh in the 2018 African Player of the Year competition won by Liverpool and Egypt star Mohamed Salah three days ago, saved Tunisian club Esperance from a Group B defeat.
The defending champions trailed 2018 quarter-finalists Horoya in Guinea from the middle of the second half when Ghana-born former Burkina Faso international Ocansey Mandela struck.
That goal separated the teams in Conakry until the fourth minute of stoppage when 2018 Champions League leading scorer Badri equalised.
Horoya were the superior side, keeping Esperance goalkeeper Rami Jeridi busy throughout, only to be deprived of victory at the death.
Antonio Souare, the multi-millionaire chairman of the Guinean club, has told his players that he expects nothing less than a Champions League semi-finals place this season.
Former champions Orlando Pirates from South Africa are away to group debutants Platinum of Zimbabwe in Bulawayo Saturday in the other Group B fixture.
Moroccans Wydad, who won the competition a second time two years ago, scored four second-half goals to trounce Ivory Coast visitors ASEC Mimosas 5-2 in Rabat.
Ismail el Haddad and Wonlo Coulibaly exchanged first-half goals before Nigerian Michael Babatunde, Zouhair el Moutaraji, Walid el Karti and Badie Aouk netted for Wydad.
Salif Bagate scored a late consolation goal for the Abidjan outfit, who did not concede in four qualifiers, admittedly against far less formidable rivals than the Casablanca club.
The triumph took Wydad to the top of Group A on goal difference from Nigerians Lobi, who came from behind to defeat 2016 champions Mamelodi Sundowns from South Africa 2-1 in Enugu.
Sundowns have never won a group game in west Africa, drawing once and losing four, including two in Nigeria, and their passing was often sub-standard.
Liberian Antony Laffor gave the visiting side a first-half lead they surrendered in the final minute of the half when Ivorian Yaya Kone levelled from a penalty.
After having an early second-half goal disallowed, Lobi took the lead a minute later with Samuel Mathias punishing sloppy defending to strike what proved the match-winner.
Abdenour Belkheir scored on 89 minutes to earn group newcomers Constantine from Algeria a surprise 1-0 win away to former champions Club Africain from Tunisia in Rades.
Record eight-time African champions Al Ahly from Egypt host 2018 CAF Confederation Cup runners-up V Club from the Democratic Republic of Congo in the pick of the Saturday matches.