Nigeria Professional Football League champions Enyimba fell to a 4-3 defeat against Al Ahli Benghazi of Libya on Sunday night.
The two-time African champions were let down by poor defensive lapses in the preliminary round first leg encounter.
Chijoke Mbaoma gave Enyimba the lead in the fourth minute.
The hosts equalised five minutes later.
Imo Obot scored an own goal three minutes before the break to hand Al Ahly the lead for the first time in the game.
Eze Ekwutoziam restored parity for the Aba giants a minute before the hour mark.
The home team restored their lead on 75 minutes.
Enyimba fought back again with substitute Murphy Ndukwu poking home from close range five minutes from time.
Al Ahly Benghazi netted the winning goal deep into stoppage time.
Both teams will clash again in the reverse fixture next weekend.