The Soweto giants are hoping to overcome a preliminary round first-leg deficit against Zambian side Green Eagles and stay alive in the continental competition.
Pirates were stunned 1-0 by tournament debutants Eagles in the first-leg clash which was played in Lusaka two weeks ago.
Since then the Buccaneers have lost coach Milutin 'Micho' Sredojevic and Mokwena is now in charge of the team on an interim basis.
The local tactician admitted the team's performance was not good enough in the first-leg clash as he looks to mastermind Eagles' downfall at home.
"We know what the Champions League means to the club. We know what it means to our supporters and to the chairman," Mokwena told SABC.
"We know what we have to do in the second-leg. We are carrying the responsibility. We accept the performance was not good enough in Zambia."
The second-leg encounter will be played at Orlando Stadium on Saturday and Pirates will need to end their four-match winless streak.
Mokwena fired a warning to the 2019 Zambian Super League runners-up.
"We know we have to make amends in the second-leg. We will make amends at Orlando Stadium because it is our home," the former Mamelodi Sundowns assistant coach added.
"It is important when they come there they feel like they are coming for a disappointment. It won't be easy for them."