The Students have suffered a debilitating run of results over the last 11 games, winning just one of those and losing six, including a run of five defeats in a row, leaving the club 13th in the standings.
However, the Clever Boys did manage to come back from a goal down to earn a 1-1 draw against Ajax Cape Town on Wednesday, lifting Wits seven points clear of the drop zone with five matches remaining in the season.
De Sa, though, hopes his side can build on that result and shake off any lingering doubts as they go in search of a loftier league position.
"I think the team is a bit scared to lose," the Dutchman said. "We certainly felt that way after losing five games in a row; it became a question of not losing.
"After we equalised (against Ajax), I sensed a bit of fear from the players and some for reason we became a bit more reserved and were scared to lose the ball up front.
"We were six points above a team (Santos) that's in a relegation battle, but we were five points behind a team (AmaZulu) in eighth position. Five is lower than six so we would rather try catch the guys that are five points ahead.
"That was the goal motivation. Hopefully we can get a win in our next match, still think we should stay positive and pursue our objective."
Wits next square up against defending champions and current PSL leaders Orlando Pirates at the Orlando Stadium on Saturday, with kick-off scheduled for 20:15.