It all felt very end of season for Rangers as ers await clarity on a takeover of the club and the managerial position. There was little at stake other than pride.
In contrast, United had it all to play for, with European aspirations alive despite three straight defeats coming into this.
Hamza Igamane missed a good opportunity before Jack Butland, who returned to Barry Ferguson's XI, rescued his side with a smart stop with Sam Dalby clean in.
From the corner, the defence were flat-footed allowing young defender Cleall-Harding to rise and power a glancing header into the far corner.
It seemed that Ibrox struggles were returning for the home side after emphatically ending a seven-game winless run last time out against Aberdeen.
That lasted just five minutes when Dessers seized on a wonderful Jefte cross to plant his header past Dave Richards, who had started ahead of Jack Walton.
The second half was, again, initially flat until Rangers were handed a chance to go ahead.
Mohamed Diomande went down under Will Ferry's challenge inside the area and Calum Scott let play go. Hwoever, he was called to review the incident and Dessers finished from the awarded spot kick.
Victory was sealed when John Souttar fed Vaclav Cerny, Raskin got beyond and emphatically thumped home past Richards.