Barker's assertion came after his side failed to bag maximum points against Platinum Stars at Princess Magogo Stadium, KwaMashu at the weekend.
Usuthu failed to penetrate the visitors’ defence with midfield trio Thabo Mabaso, Bafo Biyela and Litha Ngxabi failing to create any clear-cut chances for their strikers.
“As you saw our midfielders didn't trouble Stars much and our build up was predictable. I think if Issa recovers soon, he could end our problems of creating goals.
“He is back at training and we are crossing our fingers that he's available for our next match,” said Barker.
AmaZulu play Black Leopards in the Nedbank Cup quarterfinals in Limpopo. Midfielder Effort Sithole said they needed to up their game if they entertained any hopes of progressing to the semis.
“We didn't click well against Stars and we need to double our efforts against Leopards. They will be dangerous because they are playing at home.
“We will be boosted by the fact that we put one over them in their backyard in the first round,” said Sithole.