The Wasps travelled to Ibrox looking to produce a shock but it was the Light Blues that stung the visitors with an impressive home display in front of 25,478 fans.
Dean Shiels was excellent throughout and with 20 minutes on the clock he had put his side two goals up before Lee ‘Superman’ McCulloch hit a third with a terrific finish on 31 minutes.
The Light Blues continued to pile on the pressure after the interval and got their reward with McCulloch and Crawford netting before Barrie McKay hit a sensational late double.
With Lee Wallace out due to a thigh injury and Kyle Hutton on the bench, Anestis Argyriou came into the starting eleven at right back but the afternoon was to end in disappointment for the defender who was stretchered off at the start of the second half.
Fraser Aird was also back in the team on the left side of midfield and after a minute he won, and took, the corner kick that led to the opening goal.
His delivery was good and when the ball dropped to Shiels 15 yards out his deflected left-foot shot sneaked in at the far post with Scott Bain scrambling across his line.
It was just the start Rangers needed and on 11 minutes Hegarty cut inside and his powerful 25-yard shot went a foot over the Alloa keeper’s cross bar.
On 20 minutes it was 2-0 and again it was the Shiels that was on target.
The Northern Ireland star made clever run in behind the Wasps’ backline and having latched on to McCulloch’s reverse pass he slotted the ball home, beating Bain at his near post.
It was a nightmare start for the visitors and their supporters looked cold and frustrated as the rain started to lash down on the Ibrox turf.
But it was only to get worse for them and on 31 minutes McCulloch scored a third.
A mix up at the back meant the Gers skipper picked up the ball 30 yards goal and after dipping his shoulder to beat his marker he drilled a low shot into the opposite bottom corner from 18 yards before celebrating with the Bears in the Broomloan Stand.
It was Jig’s 15th goal of the season and before the first half was finished he almost added another to his impressive tally.
Argyriou picked him out with a superb pass and McCulloch’s first time shot dipped over the cross bar with Bain watching it closely.
As both teams strolled up the tunnel at the break the Alloa players’ heads were down and they had rarely troubled Neil Alexander.
Into the second half, however, and the Rangers keeper finally had a save to make.
Nicky Low’s free-kick went over the wall with pace but the keeper read the situation to make an easy stop.
On 54 minutes McCoist was forced to make his first switch when Argyriou fell to the turf in pain as he tried to turn in front of the East Enclosure.
The Greek defender was holding his ankle as he was taken away on a stretcher and Robbie Crawford took his place with Little moving to right back.
On the hour mark Barrie McKay also replaced Fraser Aird and the 17-year-old sub had an instant impact.
Macleod played the ball down the right channel to Sheils but his shot was palmed onto the post by Bain and the ball came back out to McKay.
The youngster tried to roll it back in from a tight angle but an Alloa defender did well to make a fine block.
The fourth goal arrived on 71 minutes and this time Shiels provided the assist for McCulloch.
The Ulsterman again found plenty of space behind Alloa’s static backline and after skipping past one challenge he cut the ball back to his skipper who had the simplest of tasks to find the net.
A minute later and it was 5-0.
Crawford played the ball down the right to Shiels and his accurate cut back found the Greenock-born midfielder who passed the ball into the net from 15 yards.
It was now a rout and, after James Doyle had been shown a red card for a poor challenge on Hegarty, McKay hit one of the goals of the season.
The youngster looked up from 25 yards and decided to unleash an unstoppable shot which flew past Bain who was left flapping at thin air.
Before the final whistle the Murray Park starlet then grabbed his second when he latched on an accurate through ball from Macleod and with his confidence high he calmly made it 7-0.
RANGERS: Alexander; Argyriou (Crawford 54), Perry, Emilson (Naismith 71), Hegarty; Little, Black, Macleod, Aird (McKay 60); Shiels, McCulloch.Subs Not Used: Gallacher, Hutton
ALLOA: Bain, Doyle, Meggatt, Gordon, Marr, Young, Simmons (Grehan 54), Ryan McCord, Cawley (Thomson 78), Homes, Low (Docherty 73)Subs Not Used: McDowall, Ross McCordSent Off: DoyleBooked: Gordon
Ref: Iain Brines