Teboho Mokoena scored the decisive goal for Bafana just before the half--hour mark as South Africa pulled three points clear at the top of Group G, ahead of the final group match against Ghana away on Sunday.
"I'm happy with the result but not with the performance, we didn't do a very good performance today, the opponent was more aggressive than us," Broos told SABC.
"They were more better on the ball, we were a little bit soft today, I don't know why, lucky for us it was 1-0 and they didn't score because they had chances also, so I can't be happy with the performance today.
"Ok, we're in a good position, we go to Ghana but we have to know the performance has to be much better on Sunday because we'll be playing against a much better team also.
"So again I don't know what happened today with my team, they were not aggressive, I don't know why but again we won the game and that is the most important.
"We wanted to change because you could see it was not good, it was not only one player, it was all the team, we tried to change somethings with other players, it was a little bit better but again. We missed the aggression today, we lost every duel and this is not good.
Broos was impressed with the goal on the night, but still wants to see more from his side on Sunday.
"Yes, it was a good opener, we scored on a set-piece, this is something where we're strong but again on the other side it was not good today, not enough and I hope we will do better on Sunday," he added.
"We're in a very good position, we're three points ahead but in Ghana if they score three times do we qualify to the next round? So we're happy with it," he added.