Mustapha side-footed effort in the sixth minute handed the People's Elephants a narrow 1-0 win in the first leg played at the Adokiye Amiesimaka Stadium, Port Harcourt.
The striker said he was happy with the goal for his club but affirmed that his focus is on their next game with the same opponents in Abidjan this weekend.
“Every player is happy to score and I will say I was too after I got that goal against Williamsville,” Mustapha told Goal.
“I have since forgotten about the goal because after we assessed the game and our opponents, we noticed that they are not to be joked with. They gave us a tough time and we were lucky to get an early goal.
“What this has shown us is that we must go to their ground not thinking about the win we got at home but what we must do to ensure that we avoid a defeat there. They played as if they were playing at home against us. They didn’t defend like some away teams would have done.
“They will be eager to attack us at home and I think it is best for us to concentrate on our preparations for the game. We need to be serious with it and explore ways by which we can keep them quiet before their fans.”
The former El Kanemi Warriors striker does not have any problem with his team’s lack of many goals and he stated that he will be happy with another one-goal win in their next game with Williamsville.
“We don’t really care about the number of goals that we scored in as much as we are winning. We won’t mind beating them 1-0 in Abidjan again next week,” he continued.
“We need to work on our defence to ensure that we do not concede needless goals. If we are able to do that, it doesn’t really matter how many goals we are able to score in as much as we are victorious.”