He praised the character shown by his teammates after coming from a goal down to beat the ABC Motsepe outfit 2-1 and advance to the quarter-finals.
Shabba was impressed with all the players who were given a run on the day, including Gustavo Paez, Kgotso Moleko and William Twala among others.
"It was a close one [against Acornbush]. We knew that it was not going to be easy. Two goals in the dying stages is character. It's experience. We came here, did the business and we move on," Tshabalala told reporters.
"Paez came in and did the job, which is good for the team. There are options on the bench. [William] Twala did very well. Rama [Mphahlele] was not playing. So, [Kgotso] Moleko came in and did well," added Shabba.
"[Celtic will be] another tough hurdle. If we maintain our work ethic and show character, then we'll get there; one game at a time. It's an away game. They are not in a good position, but we are focusing on our journey," said the 32-year-old.