In one of the noisiest nights at the stadium for a long time Ferguson’s touch of class was what mattered.
Davie Weir flicked on Steven Davis’s corner and from a really acute angle, Ferguson found the top right corner with a superb finish 17 minutes from the end.
You could sense the tension lift out of the air as the Light Blues cut Celtic’s lead to four points.
Now they march on to Saturday’s match with Dundee United knowing the same must happen again.
Dick Advocaat watched it all from the stand, sitting beside David Murray, and if he learned one thing it is that this Rangers side will not give up.
It was inevitable that Walter Smith would make changes given the astonishing schedule of matches Rangers are facing.
Papac, Cousin and Dailly all moved out of the side that face Hibs with Whittaker coming in at left back and Darcheville and Boyd coming in to a 4-4-2 set-up.
Rangers had most of the ball in the first half, but they found the Motherwell defence to be stubbornly resistant.
Boyd almost broke through in two minutes when Barry Ferguson played him in but Craigan got across to make a terrific challenge to deny the striker.
Darcheville and Boyd almost managed to combine in seven minutes but Darche’s ball was just behind his partner.
Mark McGhee’s men were hemmed in and Davie Weir connected with Steven Davis’s corner but Graeme Smith clawed the ball away and then Novo stubbed the rebound wide.
Rangers should have had a penalty in 15 minutes when Craigan clearly wrestled Weir to the turf as he tried to reach another Davis corner.
Charlie Richmond was only a matter of yards away but seemed to miss it, which is remarkable.
Having said that, there are not too many decisions going Rangers’ way these days.
With five ex-Rangers in the Motherwell line-up it was always going to be tasty and two of them almost combined to cause Rangers a real problem in 34 minutes.
Hughes burst to the goal line in a rare Motherwell attack and cut the ball back for Ross McCormack but the little striker pulled his shot wide.
Rangers recovered from that and carved out another decent chance in first half injury time but they failed to take it.
Novo picked out Boyd in the box and he worked it to Darcheville but his shot flew past the right post.
Motherwell were under siege in the first 15 minutes of the second half as Rangers turned up the heat on a balmy evening but still the goal wouldn’t come.
Davis picked out Boyd with corners in 48 and 50 minutes but the striker head wide and over on each occasion
Another corner was won in 53 minutes and this time Motherwell defended the first ball but it broke to Ferguson who fizzed a right foot drive just wide.
Then in 55 minutes only a desperate lunge by McLean stopped Darcheville’s ball reaching Boyd as Motherwell desperately hung on.
The noise was reaching fever pitch now as the fans, inflamed by a sense if injustice, roared their team on.
They thought they had their moment in 68 minutes when Darcheville used his strength to work the ball to Novo who suddenly had a free run on Smith but the former Rangers reserve keeper was quick off his line to make a great blocking save.
However, they got their wish five minutes later as Rangers grabbed the goal they craved.
Suitably it was the battling skipper, who had covered every blade of grass, who scored it.
Broadfoot won a corner on the right side and again Davis swung the ball in. Weir flicked it on and from a tight angle, Ferguson produced a fantastic finish, finding the top right corner.
The noise around Ibrox was deafening because everyone knew just how important the goal was.
Rangers might have had a penalty again in 82 minutes when Novo was sent sprawling and then Boyd had the ball in the net a minute later but was just offside.