The Baggies are bottom of the table and fell eight points from safety following Saturday's 1-0 loss to Watford on Saturday.
It was their fifth straight loss in the Premier League, but Evans remains confident they can turn things around.
"The most important thing for us is that we still believe," he said. "We're working hard. You could see that.
"The fans were receptive to that and it gave us a lift. They appreciated the work rate we put in today. We thank them for travelling."