Ajax raced to a 3-0 lead against Dikwena before holding on for their first victory of the season under new coach Stanley Menzo.
While the Urban Warriors are languishing in the relegation zone, African champions Sundowns are on a tear as their 5-0 rout of Highlands Park on the weekend was their fourth league win in a row.
However, Mosimane expects a test against the Urban Warriors at Cape Town Stadium tonight (19h30).
"Cape Town is forever difficult," says Mosimane. "Last year we drew remember. In fact we should have lost that match... The one before Tuks. I had to do damage control. If it's a draw, we had to take it.
"We are playing them at the wrong time now. They have just turned the corner. They just won in Rustenburg. They are motivated. They always up to it for us. We don't get it easy there."
Mosimane is expected to welcome back star midfielders Keagan Dolly and Khama Billiat from their respective injuries for the tie.
The Brazilians are eighth on the table with 13 points from six games - eight points adrift of log leaders Cape Town City, who have contested five more matches.
Mosimane's men are playing catch-up in the Absa Premiership owing to their arduous journey to CAF Champions League honours.