Al-Ahly of Egypt ground out a 0-0 weekend draw at CA Bizertin of Tunisia to keep on track the challenge for a record-extending eighth CAF Champions League title.
The last-16 first leg was a poor advertisement for the premier African club competition with many misplaced passes and few scoring chances before a crowd limited to 1,500 for post-Arab Spring security reasons.
Sherif Ekrami of Ahly was much busier than rival goalkeeper Farouk Ben Moustafa, making a couple of good saves before Larbi Jabeur had a late goal disallowed.
Bizertin had threatened to pull out of the Champions League last week because of a domestic dispute after being barred from the second phase of the title race over alleged match-fixing.
Ahly, who defeated Esperance of Tunisia 3-2 overall in the 2012 final, left veteran centre-back Wael Gomaa out of the starting line-up with coach Hossam Al-Badry preferring Saad Samir.
The clubs clash again early May behind closed doors in Egypt after Ahly supporters threw firecrackers on the pitch in the previous round, disrupting a home win against Tusker from Kenya.
Coton Sport of Cameroon and 2012 CAF Confederation Cup winners AC Leopards of Congo Brazzaville scored three goals each to raise hopes of overall victories and places in the lucrative group phase.
But former African title winners FUS Rabat of Morocco and Enugu Rangers of Nigeria were held at home, diminishing their chances of making the mid-May last-eight draw in Cairo.
Yougouda Kada doubled his African goal haul to four this season with a first-half brace for Coton Sport in a 3-0 success against Stade Malien of Mali in Garoua and substitute Ismael Mbang added the third late in the second half.
Ntela Kalema converted a last-minute penalty to secure a 3-1 win for Leopards over Algerian visitors Entente Setif in Dolisie after Mohamed Amine Aoudia had reduced arrears midway through the second half.
Rudy Guelord Bhebey-Ndey and Arouna Drame were on target in the opening half for Leopards, whose African success last season was the first by a Congo Brazzaville club in 38 years.
FUS, another former holder of the second-tier Confederation Cup, went ahead after 70 minutes though Brahim El-Bahri against Sewe San Pedro from the Ivory Coast in the Moroccan capital.
But Kevin Zougoula equalised, Sylvain Gbohouo saved a penalty from Mourad Batna and FAR had a goal disallowed in a frenetic finish at Stade Prince Moulay Abdellah.
Landu was another goalkeeper to excel, making a series of superb saves to foil Enugu to earn hyper-cautious Recreativo Libolo a 0-0 draw, and tilt the balance toward the Angolan provincial club.
The eight aggregate winners after the May 3-5 return matches advance to the mini-league phase while the losers drop down to play-offs against Confederation Cup last-16 winners.