And with another two added in the dying stages the result and a meeting with Hamilton in the quarter finals were never in question.
Any pre-match nerves that may have existed among the visiting squad were settled when the opening goal came with just seven minutes on the clock.
Despite the reinstatement of Kris Boyd and Kenny Miller as two of six changes in the Rangers line up the breakthrough came from the least likely of sources – Sasa Papac.
The Bosnian left back found himself in an advanced position as Gers dominated the early stages and he was on hand to finish when the ball broke from Miller after some neat build up featuring Maurice Edu.
That threatened to open the floodgates as the visiting side showed the gulf between the two teams but with home keeper Alistair Brown on sparkling form Forfar kept themselves in the match.
The shot stopper produces a couple of great saves to deny Beasley’s powerfully struck shot on the half hour after he was played in by Miller.
He went one better with six minutes of the half remaining when he denied Miller who produced an acrobatic overhead kick from Boyd’s header only to see Brown palm the effort away.
Those two saves sandwiched Forfar’s best spell of possession which saw them win a series of corners, ended only when Andy Tod’s effort flew by Allan McGregor’s upright.
The halftime scoreline didn’t reflect the dominance Rangers had enjoyed but the visitors almost gave themselves the cushion they needed five minutes in to the second period.
Beasley supplied the creative spark to pick out Boyd who buried his shot beyond Brown only to see his celebrations cut short by an offside flag.
A second wasn’t long in coming though as Boyd’s striking partner Miller pounced on a poor clearance just three minutes later.
He took a touch and sent a left foot strike high beyond Brown to give Gers the goal their play deserved.
Boyd would be denied the chance to join his attacking mate on the score sheet when his involvement was ended in the 65th minute as he made way for Kyle Lafferty.
Just four minutes later Elliot Smith joined Boyd in departing the field as he saw a straight red flashed after he felled Beasley with a two footed challenge wide on the Rangers left.
Although the American eventually got back to his feet after attention from the Ibrox medical team he was quickly replaced by Aaron as the coaching staff refused to take any risks with the US wideman.
With the game slipping away from his side Dick Campell made a double change, introducing Martin Fotheringham and Mark McGuigan for the midfield pairing of Craig Winter and Darren Brady.
It was Aaron though who had the greater impact as his willingness to run at ten-man Forfar caused the home side no end of problems.
And when he collected Lafferty’s pass with seven minutes remaining he made no mistake in front of goal as he slotted comfortably past Brown for his first goal in a Rangers shirt.
He quickly lost that shirt in celebration, collecting a yellow card for his troubles.
With the match over as a contest Rangers were able to show their greater quality and they added gloss to the scoreline when Miller grabbed his second of the night after Lafferty found him lurking in the six yard box.
Lafferty then came close to adding a fifth in injury time but his left foot effort from the edge of the box was beaten away by Brown.