Any debate over a closing of the gap between Celtic and Rangers this season was shut down emphatically by the Scottish champions as they marched imperiously into the William Hill Scottish Cup Final at the expense of their crestfallen Old Firm rivals.
The gulf in quality between the teams remains as wide as it has always been during Brendan Rodgers tenure as Celtic manager which now sees him firmly on course for the unprecedented feat of winning back to back domestic trebles.
Motherwell will stand between Celtic and that piece of Scottish football history in the Hampden final on 19 May but the tournament sponsors are unlikely to receive too many bets on the Fir Park club upsetting the odds.
While Celtic savoured their biggest Hampden win over Rangers since the 1969 Scottish Cup Final, this was an agonising day for Graeme Murty whose prospects of remaining as manager of the Ibrox side beyond the summer have probably been fatally undermined.
First half goals from Tom Rogic and Callum McGregor put Celtic in total command before Ross McCrorie’s dismissal early in the second half left Rangers in a hopeless situation. Celtic capitalised with successful penalties by Moussa Dembele and Olivier Ntcham as they ultimately cruised through.
From the opening seconds, Celtic carried the demeanour of a side determined to underline their status as the country’s best in the boldest letters possible. They were superior in every department - physically, technically and tactically overpowering Murty’s players who appeared painfully cowed and uncertain in comparison.
The cup holders could have been ahead as early as the fifth minute when Dembele, whose appetite for these type of occasions is so often in sharp contrast to his occasionally disinterested contributions in more run of the mill games, latched onto Ntcham’s cross from the right and cracked a volley against Wes Foderingham’s left hand post.
With Dembele in this mood, it quickly became evident this was going to be a long and difficult afternoon for Rangers’ central defensive pairing of McCrorie and Russell Martin.
The French under-21 international striker burst into the penalty area again five minutes later, fastening onto Rogic’s pass, but this time was denied a shot at goal by McCrorie’s timely intervention.
Celtic remained firmly on the front foot and Dedryck Boyata should have broken the deadlock in the 21st minute when he wastefully glanced a close range header wide after being picked out by a McGregor corner.
But Rodgers’ side only had to wait a further minute to take their fully deserved lead. Dembele and James Forrest linked up superbly down the right to stretch the Rangers defence with the winger squaring the ball across the face of the box into the feet of Rogic.
The Australian playmaker turned cutely away from the wrong-footed McCrorie and slotted a precise right foot finish beyond Foderingham’s left hand into the corner of the net.
Rogic should have doubled Celtic’s lead in their very next attack, finding himself on the end of another fine move but this time only able to direct a tame shot straight at Foderingham.
Rangers struggled desperately to find any kind of meaningful response. Daniel Candeias, so often one of their shining lights this season, was unable to produce a telling final pass or cross whenever he did find himself in promising positions, typified by a low cross easily cut out by Boyata when Alfredo Morelos was waiting unmarked.
That was as threatening as Rangers managed to be in the first half and Celtic finally put a more realistic sheen on the scoreline when they made it 2-0 seven minutes before the break. The goal was a calamity for Martin, the veteran Scotland international’s weak attempt to clear a Kieran Tierney cross merely guiding the ball straight into the path of McGregor who curled a smart right foot shot beyond Foderingham.
Murty’s immediate response was his first substitution of the afternoon, replacing Andy Halliday with the more attack-minded Josh Windass. Halliday, who was making his 100th appearance for Rangers, didn’t take it well as he mouthed off angrily as he made his way off the pitch.
Before the reshaped Ibrox team had the chance to try and claw their way back into the contest, they found themselves 3-0 and a man down just seven minutes into the second half.
There could be no dispute about referee Bobby Madden’s decision to both award Celtic a penalty and send McCrorie off as the young defender found himself on the wrong side of Dembele and tugged his shirt to pull him down just as the striker was lining up a shot.
Dembele rubbed salt in Rangers’ wounds with his almost contemptuous conversion of the spot-kick, sending Foderingham the wrong way as he dinked a chip into the net.
Murty made another change, attempting to shore up his short-handed side with the introduction of Bruno Alves for Candeias who indicated his displeasure at the decision by storming straight up the tunnel.
It was very much a lost cause for Rangers already but they contrived to produce their best spell of the afternoon in the 10 minutes after McCrorie’s red card. Craig Gordon was finally called into action, making two excellent one handed saves in quick succession to keep out headers from Morelos and Alves as Rangers searched for some consolation.
But Morelos’ woes in front of goal in Old Firm fixtures continued when he missed a clear chance in the 57th minute. It wasn’t as glaring as the one he fluffed against Celtic at Ibrox last month but, after Mikael Lustig had sliced the ball against his own crossbar, the Colombian should have done better than drive a low shot straight at Gordon who made a comfortable save.
There would not be even the slightest crumb of comfort for Rangers and a joyous afternoon for the Celtic fans was sealed by their team’s fourth goal, again from the penalty spot, with 12 minutes remaining.
Rangers substitute Jason Holt’s challenge on Celtic replacement Patrick Roberts sent the winger tumbling and gave Madden another straightforward decision to make. Curiously, Dembele gave up the chance to add to his tally against Rangers, handing the responsibility to Ntcham who made no mistake with a sweetly struck penalty which beat Foderingham low to his right.
Celtic: Craig Gordon; Mikael Lustig, Dedryck Boyata, Kristoffer Ajer, Kieran Tierney; Scott Brown, Olivier Ntcham; James Forrest (Patrick Roberts 73), Tom Rogic (Scott Sinclair 60), Callum McGregor; Moussa Dembele (Leigh Griffiths 79). Subs not used: Scott Bain, Jozo Simunovic, Eboue Kouassi, Odsonne Edouard.
Goals: Rogic 22; McGregor 38; Dembele 52; Ntcham 78.
Booked: Lustig, Brown.
Rangers: Wes Foderingham; James Tavernier, Ross McCrorie, Russell Martin, Declan John; Andy Halliday (Josh Windass 41), Greg Docherty, Graeme Dorrans (Jason Holt); Daniel Candeias (Bruno Alves 53), Alfredo Morelos, Jamie Murphy. Subs not used: Jak Alnwick, Lee Hodson, Kenny Miller, Jason Cummings.
Booked: Docherty, Dorrans, Morelos, Tavernier.
Sent off: McCrorie.
Referee: Bobby Madden