The Fir Park side may be languishing at the bottom of the league but they were the better side for large chunks of an eventful semi-final and can maybe feel aggrieved that it is Rangers and not they who will face Dundee or Inverness Caley Thistle on May 31.
Aside from an early goal, it was the Fir Park side who dominated play and deservedly forged into a 2-1 lead before three strikes in the second half eventually handed Rangers a place in the final.
It was hardly convincing with a vital Old Firm game fast approaching but such a struggle had seemed unlikely after a storming start from Rangers.
The Light Blues had been expected in many circles to mercilessly crush Motherwell and within a minute that presumption was given extra credence when the Light Blues took the lead.
Barry Ferguson, back from suspension, made space down the left wing and rolled an inviting pass to Bert Konterman who drove the ball powerfully past Francois Dubourdeau.
That strike, however, was to prove something of a false dawn with Motherwell unwilling to lie down and let Rangers dominate them.
Backed by a small but boisterous support, the Fir Park side took the game to Rangers throughout the remainder of the first half and looked threatening every time they ran at a nervy-looking Light Blues defence.
Alex McLeish’s first choice central defensive partnership of Lorenzo Amoruso and Craig Moore was re-united for the first time in five matches but they looked ill at ease as the spritely pairing of David Clarkson and Steven Craig made darting runs in behind them with increasing regularity.
And then there was the influence of James McFadden. All the focus in the build-up had been on the precocious 20 year-old and he didn’t disappoint with the glare of the spotlight fully on him.
Playing wide on the right, he was involved in Motherwell’s first two goals and looked menacing every time he came into contact with the ball.
Rangers’ early lead lasted all of 14 minutes. Amoruso was hurried into a rash clearance by McFadden allowing Martyn Corrigan to sail forward and find Clarkson with a through ball that left the Light Blues’ defence flat-footed and appealing in vain for an offside decision.
Clarkson crossed for Craig and he bundled the ball beyond Stefan Klos for a shock – but wholly deserved – equaliser.
Without the creative genius of Ronald de Boer – missing with a calf injury – Rangers looked bereft of inspiration and with 27 minutes gone they were trailing.
Craig’s ball into Stephen Pearson was only half-cleared by Amoruso and the waiting McFadden curled a left foot shot beyond the dive of Klos and high into the net.
Stunned into action, Michael Mols had a great chance to equalise minutes before the break but lost his footing at the vital stage and shot wide of the gaping goal.
It could have been much worse for Gers if Clarkson had converted from close range after a slip by Amoruso but they still faced the unsual experience of heading up the tunnel at half-time a goal behind.
Galvanised by harsh words from McLeish or perhaps just an awakening of their pride, Rangers looked much sharper in the second half and within 15 minutes they were back in front.
Fernando Ricksen had a key role in both strikes and it was his pass that released Steven Thompson – on as a half-time substitute for Shota Arveladze – to bore in on goal.
The former Dundee United striker timed to perfection his through ball to Mols and the Dutch striker powered a low shot past Dubourdeau to draw Rangers level.
Two minutes later and events turned once more in the Ibrox side’s favour as they went in front again.
Neil McCann won a free-kick wide on the left that Ricksen centred for Amoruso to bullet a header home.
Motherwell – stung by the speed of that sudden turn-around in the scoreline -looked deflated in the knowledge that they would have to score again to just force a replay.
With 18 minutes to go, Rangers killed the match with a fourth goal when Kevin Muscat worked a 1-2 with Ricksen and crossed into the box where the unlucky David Partridge nodded beyond his own goalkeeper.
Motherwell had the last say in the match when Derek Adams grabbed a late consolation goal as Rangers held on to book their return to Hampden in less than convincing fashion.
RANGERS (4-3-3): 1 Klos; 17 Muscat, 3 Moore (Malcolm 75), 4 Amoruso, 5 Numan; 2 Ricksen (Hughes 78), 15 Konterman, 6 Ferguson; 24 Arveladze (Thompson 46), 10 Mols, 11McCann
Subs not used: McGregor, Maclean
Booked: Mols (22), Moore (22)
MOTHERWELL (4-4-2): 13 Dubourdeau; 2 Corrigan, 14 Partridge, 15 Vaughan, 3 Hammell (Cowan 74); 10 McFadden, 6 Pearson, 8 Leitch (Lehmann 85), 7 Adams; 27 Clarkson, 17 Craig (Offiong 68)
Subs not used: Woods, Lasley
Booked: Vaughan (22), Adams (22), McFadden (82), Pearson (85), Offiong (90)
Man of the Match: Michael Mols