Interim head coach Ferguson sprung a surprise by deviating from a back four, with Ridvan Yilmaz as right wing-back and James Tavernier on the right of a three.
And Rangers were dealt a gift when Mohamed Diomande pounced on Sebastian Szymanski's slackness and Dessers rounded Egribayat to finish.
The visitors' positive start was almost undone when Robin Propper and goalkeeper Jack Butland collided on the edge of the box, John Souttar coming to their rescue.
Propper came off worst and had to be replaced. And, within minutes, Rangers had lost their advantage as Nico Raskin's wayward header was swept home by Djiku.
Rangers were now looking to hit on the break and one such attack paid off as Cerny exchanged passes with Dessers to angle a low shot past Egribayat.
More questionable defending allowed Dessers to force in after a Jefte shot was blocked but the travelling fans' celebrations were halted when replays revealed Dessers' shoulder had been ahead of the last defender.
Rangers tried again, though, and Jefte released Dessers to force past Egribayat again. Again there was a lengthy pause and again the hosts were given a reprieve.
But Fenerbahce could only watch on as Raskin, deep in his own half, released Cerny to speed beyond the defence and slot home.