Clarke, who has seen his team struggle for form over recent weeks - the Saddlers losing six league games on the bounce heading into last weekend's cup clash - doesn't believe there is a lack of effort but more an issue with mentality.
Clarke's Saddlers looked to be heading out of the competition with five minutes of the second-half remaining as they had fallen a goal behind seventeen minutes into the first half as Omar Holness slotted the ball past on-loan Southampton stopper Jack Rose.
But, after the manager had opted to make a double change midway through the first-half, the Reds were able to regroup and went on to put themselves a goal ahead in three second-half minutes as Caolan Lavery (86') and a Alfie Bates-assisted Liam Connell own goal (89') looked to have booked their team a place in the Second Round.
However, Saddlers hearts were ultimately broken as Josef Wheatley was on hand to level the scores deep into second-half stoppage time giving the Saddlers another unwanted match and extending their run of winless games.
Walsall, however, saw several chances spurned as both Elijah Adebayo and Rory Gaffney saw opportunities to put the game out of the reach and Mansfield-born Clarke was left bemoaning his side's dismal form in front of goal.
Speaking to the assembled media, Darrell said; "You watch in disbelief sometimes at the chances that we keep throwing away and the decision making of the players. I’m not telling them not to take shots, they’re doing it for fun in training but it’s a mindset isn’t it.
"I have some real good coaches that are working with these boys every day and they’re doing the business in training but not in matches. That can only be a mindset thing. I genuinely said in there, I don’t think they’re used to being winners, some of them really don’t know how to win.
"Some of the younger players have got to get that and get it quick. You guys watch the same game as me, how many golden chances did we miss. A couple, Gaffney open goal as well.
"Hopefully Lavery comes back and he shows his confidence to put it into the back of the net. But we have to keep working with these players, it can change quickly. There was not a lack of work rate or effort, because you don’t create the chances that we create to win a football game.
"You wouldn’t be asking me that question if we had scored three or four goals. People can get a little bit deluded and say they’re not trying. If we score those four goals, that should be goals, people wouldn’t be saying they’re not trying.
"The fact of the matter is that there’s a weak mindset and a softness, not a lack of desire. But it’s a fine line between both as in, putting yourself in positions to make errors as well. But I’m not having a go at them for a lack of effort."