The Reds go into this weekend's clash with the Robins on the back of a run which has seen them notch five defeats on the bounce and are in desperate need of a return to form as they continue to battle towards the foot of the table.
Clarke, who has called for supporters to stick with his team, insisted there were some positives to take from last weekend's defeat to Mansfield Town but went on to admit his side must do better in the crucial moments in order to turn their fortunes around.
Speaking via the club's official website, Darrell said; "I get sick of repeating myself but there have been so many games this season where we haven’t taken the key moments and then we get punished at the other end.
"Against Mansfield we missed a one on one and then a minute later the ball ends up in the back of our net. In the last five games we’ve been very sloppy with our defensive performances but there were some positives Saturday.
"There are one or two out of form and the shirt is weighing a bit heavy on them at times but collectively we’re working very hard.
"There’s no problem with the distance we’re covering in games, the amount of sprints we’re making and I don’t think there’s any question about their desire.
"We’ve had two or three players out but the quicker we get out of it the better. We’re hoping to have one or two back this weekend that we need.
"They’ve had a bit of grass time, a bit of training time. It will be nice to get a few back. We’re at that stage where you get one or two players out and it has a massive impact."