The Bafana Bafana ‘B’ side advanced to the last four as Group A winners, thanks to a superior goal difference after finishing level on four points with Zimbabwe and Mozambique.
Having only scored two goals in three matches, Khumalo has called for improvement in Friday’s semi-final.
"Let me start by congratulating our opponents, Mauritius, they gave us a good assignment to work on, we couldn't break them, they played a low block and wanted to hurt us in set-plays, we were well aware of that," said Khumalo.
"But I think what has always been the problem with us, since the beginning of the tournament, was not being clinical – we're not scoring goals.
"We create the chances and get the entries into the final third, we stretch them with width, we go inside, we go with combinations, but the one thing we're not doing well is scoring the goals.
"So I think, more than anything in this tournament so far, it has always been us not scoring goals."
SABC Sport understands that they will be minus the services of Kaizer Chiefs striker Wandile Duba, who has left the camp for reasons unknown at this stage.
Should Botswana beat Zambia today by more than one goal, they will leap-frog current leaders Comoros in the three-team group but, either way, Khumalo says they will have to be at their best for their next opponents.
"We are well aware that football is going with technology now, other teams are going to do much analysis on us, and if you have realised, we have been playing two systems, but as we check who we are going to play against, it will require us to also change a little bit," he added,
"More than anything else, we don't have time, we need to adapt as soon as possible and change the system as soon as possible, according to how we want to play to our strength as well, but I think the preparation will be thorough for the semi-final."