Ajax lost to their new neighbours via Bongolethu Jayiya's 21st minute strike at Cape Town Stadium on September 23.
The Urban Warriors, who are yet to win in four league games this season, were also left sweating over injuries to defenders Rivaldo Coetzee and Mosa Lebusa.
“Obviously I am disappointed having lost. It was end-to-end, and it didn’t stop. We started okay and created half chances,” De Sa is quoted as saying on the club's website.
“We tried to get back in the second half, but never got a go at it. Credit goes to City from stopping us from playing. We suffered those injuries and tried to change things up. We went three at the back and pushed one forward. But we couldn’t score…
“We have got two defenders off with injuries and that is a bit of a concern. Fortunately, we do have a bit of break before our next game. The Wits game got postponed so we do have a two-and-a-half week break before our next match. Hopefully we can rectify a few things.
“Some of our players have it, some don’t. It is in these situations where you can see who has a heart the size of a peanut and who has a proper heart. That is what you learn from having a young squad,” concluded the former Orlando Pirates mentor.