Barker's side have had a dream start to the league so far this season as they occupy second position in the DStv Premiership standings.
The Cape side impressively is also yet to taste defeat after eight matches played - three points off leaders Mamelodi Sundowns - with a tally of 16 points.
The experienced tactician singled out the Bafana Bafana international in a rejuvenated Kaizer Chiefs side ahead of their clash on Tuesday.
"I think he's obviously showing the quality that he has and that everyone knows he possesses," Barker said.
"We know we can't allow him the freedom and space, especially in the final third.
"But it's just not only him, but the movement of their front-three also is really good and they've got good quality midfielders.
"Defensively they are solid, so there are signs of a team that are well-coached which is starting to show at Chiefs.
"So, there's a number of players that we need to be aware of, but yes Keagan does pose a big threat for us."
Kick-off is at 15:30.