Barry Ferguson admitted opponents "don't fear playing Rangers" any more as they were left without a win in five matches after drawing with St Mirren on the day that Celtic officially clinched the Scottish Premiership title.
Rangers' interim head coach had urged his side to respond to the hurt of failing to mount a title challenge by winning their final five games.
But, despite Cyriel Dessers and Nicolas Raskin putting Rangers ahead in each half, they were quickly pegged back twice by Mark O'Hara and Conor McMenamin.
"When you speak to them individually and as a group and you ask them to do things and they don't do it, what is the point?" Ferguson told BBC Sport Scotland.
"That's the thing that frustrates me.
"The issue I've got is people don't fear playing Rangers now. Whether that's at home or away, they enjoy coming to Ibrox.
"And then, when you go away from home, teams look to see if they can bully you, run hard at you and get in about you."
Ferguson had been hoping to impress enough to secure the job on a permanent basis but has won just four of his 11 games in charge.
Errors by centre-back John Souttar and goalkeeper Liam Kelly presented St Mirren captain O'Hara and Mikael Mandron with early opportunities to open the scoring, while Dessers blasted wildly over at the other end.
Dessers made amends when Rangers took the lead with their first flowing move, the striker collecting Raskin's low pass, turning his marker and firing low past goalkeeper Zach Hemming.
However, when a long throw-in deflected into O'Hara's path, the midfielder swept it home from 15 yards.
Rangers were back in the lead after the break when Raskin gathered Diomande's pass and poked a low drive past Hemming from the edge of the penalty box.
St Mirren should have been back level when Souttar again dallied on the ball, Phillips' backheel put Roland Idowu in the clear, but his shot came off Kelly's legs.
The equaliser eventually came when Declan John's low cross was turned into the net by the sliding McMenamin.