In scenes reminiscent of last season’s embarrassing stalemate at Berwick Rangers, the Light Blues missed a host of chances throughout the 90 minutes and were perhaps fortunate to finish the tie off at the first time of asking.
The start of the second half had been delayed for a few minutes to allow for essential repairs to one of the goal nets.
Following a woeful first period where neither side looked capable of breaking the deadlock, you began to wonder whether the nets were required at all.
As expected, Rangers had the lion’s share of possession but were unable to break down an Ayr defence that hunted every player in Light Blue down as soon as they received the ball.
The home side lined up in a 4-4-2 formation but they had nine players blocking the way to goal every time Rangers poured forward in attack.
Alex McLeish’s men, however, seemed unable to find a way through or around this sea of white shirts and were often guilty of being over elaborate when in close proximity to Nelson’s goal.
Ayr, as could be expected from a lower league side, were happy to defend deep, play on the counter attack and battle for every ball.
They signalled their intentions early on when James Grady clattered into Lorenzo Amoruso with less than two minutes on the clock, with the Italian requiring treatment before returning to his post.
Mikel Arteta was not so lucky and limped off with an ankle injury – with Stephen Hughes his replacement- midway through the first half to further weaken a Rangers side missing flu-ridden Fernando Ricksen.
De Boer was given the responsibility of being the Light Blues’ main creative influence but none of his team-mates seemed able to feed off his probing passes.
With the penalty area seemingly a no-go area, Barry Ferguson, Bob Malcolm and Shota Arveladze all had attempts from distance that sailed harmlessly into the terraces behind Nelson’s goal.
It was not the greatest of days for Arveladze – on his 30th birthday – as he passed up several other decent chances, although he came closest to scoring in a lacklustre first half when he rattled the junction of the crossbar and post after 24 minutes.
A minute later he had the ball in the net when he latched on to de Boer’s neat pass but he had wandered offside.
As Rangers continued to pass up a host of decent chances, Ayr’s confidence took a visible boost and the front pairing of Grady and Steven Whalen were proving a handful for the Rangers defence.
As the half drew to a close, Grady nutmegged Moore and was promptly hauled to the ground, although the resulting free kick came to nothing.
Rangers were getting gradually closer to Nelson’s goal and Hughes had a shot blocked before Arveladze’s unnecessary overhead kick was over-elaborate in front of goal.
Arthur Numan – in his last season with Rangers – was then booked for a dispute with Grady before the Dutchman’s long-range effort was punched away by the goalkeeper.
The Light Blues were getting increasingly desperate and McLeish threw on Claudio Caniggia and Steven Thompson to further boost the attacking options.
With a replay looming, Rangers finally opened the scoring. Caniggia fed fellow sub Thompson down the line and his perfect cross was headed in at the back post by de Boer to the visiting support’s audible delight – and relief.
Ayr had a late rally – sub Stewart Kean had a great chance to lob Stefan Klos before Grady blazed a shot over – but Rangers held on to squeeze into the Fifth Round.
AYR UNITED (4-4-2): 1 Nelson; 2 Lyle, 4 Campbell, 5 McManus, 6 Craig; 7 Chaplain, 8 Smyth, 11 Murray, 3 Lovering; 10 Grady, 9 Whalen (Kean 73)
Subs not used: Dunlop, Nicolson, Latta, Dodds
Booked: Smyth (81), Grady (83)
RANGERS (4-3-3): 1 Klos; 17 Muscat, 4 Amoruso, 3 Moore, 5 Numan; 23 Arteta (Hughes 21), 12 Malcolm (Thompson 62), 6 Ferguson; 14 de Boer; 24 Arveladze, 11 McCann (Caniggia 73)
Man of the Match: Ronald de Boer