Matthew Rusike looked to have earned the Chiefs a late draw in Sunday's first leg with an 86th-minute equaliser, but ASEC edged ahead once again in the second minute of stoppage time, as Koffi Davy Boua notched a second away goal.
Chiefs coach Stuart Baxter was livid after the match and, further to claiming his side lost to "a poor team", blasted ASEC for displaying what he perceived to be unsportsmanlike behaviour.
"I don't think you've got any idea what it's like playing against a team that’s throwing themselves on the ground," said the 60-year-old following criticism of his team selection.
"I call that cheating. If you want to lambast players who worked their socks off, you have to look at the tactical conditions for the match.
"What I don't like is lack of endeavour, passion and commitment from my players, and I told them in the change room.
"I still think we fielded a strong enough team. The bubbly pitch and the opponent's time-wasting antics tactically affected the flowing football that we wanted to play.
"We dominated play territorially and should still have won the game."
Baxter's men are also in the hunt for domestic league and cup glory in South Africa this season.
The coach added: "We are going through a gruelling, traumatic period in which we are competing for honours in three different events at the same time."
Ahead of the second leg in Abidjan on Sunday, the Chiefs can at least take heart from their recent away form, which has seen them lose only three of their last 18 games in all competitions.
Egyptian giants Al Ahly go into their second leg against Difaa El Jadida with a narrow 1-0 lead after defeating their Moroccan opponents at home on Sunday.
Difaa have now failed to win any of their last five in all competitions, while Al Ahly are on a four-game winning streak and will be confident of progressing.
Real Bamako make the relatively short trip to face fellow Malian side Djoliba on Friday hoping to hold on to a 2-1 lead from the first leg, while Guinean outfit Horoya face a difficult test at Etoile Sahel following a 0-0 draw at home.
Sewe Sport's 2-0 defeat of Bayelsa United leaves the Nigerian side with a mountain to climb against opponents who have suffered only three losses in 26 matches.
Ghana's Medeama also have a tricky second leg ahead of them as they host Leopards de Dolisie, whom they lost 2-0 to on Sunday.
Congolese outfit Leopards go into the return fixture having lost only once in 24 fixtures across all competitions.
Cotonsport take a narrow 2-1 lead to Angola ahead of their showdown with Petro de Luanda, while it is all to play for in Tunisia as Bizertin entertain Nkana on the back of a 0-0 first-leg draw.
