But Magilton spent the last few minutes in the stands after being ordered away from the dug-out by referee Graham Salisbury.
Magilton was unhappy to see winger Wayne Routledge booked for diving in the box as he tried to take the ball round keeper Joe Murphy.
By then though, the London side were well on their way to that first victory, thanks to a third-minute goal when winger Adel Taarabt waltzed all too easily through the middle of the home defence to flick his shot past Murphy for the only goal of the game.
And it might have been 2-0 just minutes later when midfield man Mikele Leigertwood forced his way into the box to get in a close-range shot that Murphy just managed to block.
Rangers, with striker Jay Simpson making his debut on loan from Arsenal, always looked dangerous going forward against a suspect Scunthorpe defence which had already conceded 12 goals in the previous four league games.
At the opposite end Scunthorpe struggled as an attacking force to get much on target against a solid Rangers defence in which centre-backs Fitz Hall and Matt Connolly were outstanding figures.
The biggest test for goalkeeper Radek Cerny came in the closing stages when he did well to turn away a free-kick from substitute Grant McCann.
Scunthorpe huffed and puffed in search of an equaliser but things just would not drop for them in and around the box.
It was Rangers that might have added to their score in the second half when centre-back Hall had a shot well-saved by Murphy following a corner.
And in the closing stages substitute Rowan Vine lashed a shot over from close range after a strong run into the box.