Ahly were punished for a sluggish display in Niamey when USGN struck a 75th-minute equaliser to cancel out Ali Maaloul's penalty in the first half.
Coach Pitso Mosimane, who was given a vote of confidence by Ahly despite recent lackluster displays, came under fire once again from the team's demanding supporters.
He urged caution as Ahly aim to seal smooth passage to the group stage and avoid any shocks.
"I am not happy with the result. We came here to win but we did not get the result we wanted but it is not easy to play here under these conditions," Mosimane said after the first leg.
"We like to focus on the positive side. We scored a goal but unfortunately, in the end, we conceded a goal. We defended very well until the goal we conceded."
Ahly welcome back key winger Hussein El-Shahat, who missed the first leg due to a muscle injury, and in-form winger Magdi Afsha, who was not available for the away clash for personal reasons.
The team's new signings, including Mozambican winger Luis Miquissone, South African forward Percy Tau and Egyptian striker Hossam Hassan are also out as they haven't yet been registered in Ahly's African roster.
USGN coach Zakari Yao Ibrahim said he will focus on Ahly's weak points in the second leg in Cairo.
"Having seen Ahly's tactics in a full game in the first leg, we can now work on exposing their weaknesses in the second leg."
USGN had booked their place in the second preliminary round of the Champions League after beating Le Messager Ngozi of Burundi 2-1 on aggregate last month.
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