Usuthu are the only club without a win this season, as they prop up the Absa Premiership standings with three points from seven fixtures.
Van Heerden told his team's official website: “We just got to keep fighting. We have to keep working hard and our fortunes will change. Things will change for us.
“We just have to put the effort in, hard work always pays off. We need to make sure we’re doing that little bit extra and that we bury our chances at the end of the day.”
The Durban outfit recently lost 2-0 at Bidvest Wits, with Van Heerden's teammate Bornwell Mwape feeling luck was against them.
He added: “It was a tough game, we worked as a team and we tried but we had a bit of bad luck.
“There’s in no need to look down because we still have many games to go. We need to push ourselves but there is no need to look down.”