The pre-match headline was captain James Tavernier dropping to the bench and it was clear Clement wanted his side to be well structured and hit effectively on the counter. They managed that so effectively throughout.
As the hosts tried to build pressure, Rangers pounced on a number of occasions. Dessers was sent clear down the left and raced in on goal, but lacked the required conviction and fired a poor effort straight at Kostas Tzolakis.
Another, even better chance, arrived shortly after. Dujon Sterling found Vaclav Cerny, who in turn laid it into Dessers, but he could only fire straight at the goalkeeper once again from six yards. The frustration was palpable.
Olympiakos continued to try and mount pressure but Rangers remained solid, restricting them to half-chances as they continued to pick their opponents off.
Jose Luis Mendilibar tinkered at half time and got a quick response. The, until then, subdued star striker Ayoub El Kaabi checked, found acres of space and swivelled to fire a brilliant shot off the underside of the bar beyond the exposed Jack Butland.
The noise - and threat - rose considerably but Rangers responded. And it was Dessers who found his shooting boots with a crisp finish.
The game opened up but neither side could find a winner.
Rangers will be by far the happier, though, as they took a significant step towards potentially securing progression to the latter stages of the competition.