The Ibrox club were held to another shock result by Irn-Bru Third Division minnows Stirling last night as they threw away a first-half lead to draw 1-1.
Andy Little had put Ally McCoist's men ahead with his 22nd strike of the season but the Binos - who stunned Rangers back in October when they became the only team to beat them on league duty this term - levelled six minutes after half-time through Ross Forsyth's header.
The goal was teed up by midfielder Kieran McAnespie's whipped-in free-kick as Stirling capitalised on the Light Blues' softness at set-pieces.
Those frailties were also exposed in the team's 3-1 weekend win over Berwick as Anestis Argyriou was forced to put through his own goal as he failed to deal with the hosts' quality corner delivers, while Dundee United showed up the Ibrox defence as well in last month's William Hill Scottish Cup showdown.
Now Scotland international Wallace insists enough is enough.
He said: "It's hugely disappointing, considering we do a lot of work on it. The manager spends a lot of time on the training field doing a lot of work on that, in particular, the wide-area free-kicks.
"And the one message he did give us at the start of the game was not to give away cheap free-kicks. But we did that on more than one occasion against Stirling and obviously that led to the goal.
"We have all just got to take more responsibility, all of us in that line. It's something we will have to try and rectify asap.
"We have done a lot of work on it. There is a lot of detail put into it. We do a lot of video as well. A lot of video on the opponents' stuff. We know what these guys are capable.
"It was similar to Berwick. Lee Currie had a good left foot and it was the same at Stirling. We know that if we give away stupid fouls they have a great chance of scoring."
While the Stirling stalemate is embarrassing for the Glasgow giants given that Forthbank is now the only Third Division venue at which they have now failed to triumph this term and that their opponents sit a huge 37 points behind them, it will do little to slow their march to the title.
Even with the two points dropped, Rangers still boast a 20-point lead at the table summit over second-placed Queen's Park.
But Wallace admits even that fact does not distract from the players' disappointment at their performance against Albion.
He said: "The result is a real frustration. It's a bit gutting and it wasn't a great dressing room after the game. It felt like a defeat.
"We went there hoping to win the game. In the first half, I thought we played quite well. We were quite fluent in our passing, played to quite a quick tempo and limited their chances.
"Andy Little scored a great goal while I had one later in the half that I maybe should have done better with. We went into the second half but it wasn't the same really.
"We didn't play with the same fluency we did in the first half and they kind of took over, to be honest.
"We are bitterly disappointed to lose that equalising goal, especially from a set-piece."
Meanwhile, Rangers defender Ross Perry's season could be over after a scan revealed he had torn his hamstring.
The centre-back suffered a recurrence of the injury during his side's 3-1 win at Berwick on Saturday and tests have indicated he faces six weeks on the sidelines.
The club said on their official website that it would be mid-April before the Scotland Under-21 defender is fit and he might not be risked again in this campaign.