With a 2-0 lead at half-time thanks to goals from Charlie Adam and Chris Burke the match officials strolled on to the turf at half-time to inspect the surface but the groundsmen made sure the pitch was playable for the second half.
The weather may have been horrendous but this did not dampen the spirits of the home support who watched their team get back to winning ways under the new management team of Smith and Ally McCoist who celebrated two more strikes from Kris Boyd and another from Ferguson as if he had stuck the ball in the net himself.
This was never going to be the prettiest football match in the world but three points is all that mattered and the Gers’ deserved their win after a hard-fought 90 minutes.
Smith made three changes to side that faced Dunfermline in the Scottish Cup on January 7 with Burke, Dado Prso and Jeremy Clement replacing Gavin Rae, Nacho Novo and the departed Julien Rodriguez.
The big question on everybody’s lips was who would be picked as captain. And it was Barry Ferguson who was once again given the armband he put in a fine display alongside Clement in the heart of midfield.
The match started tentatively with both teams trying to retain possession while trying to keep their feet..
Chances were few and far between in the opening ten minutes although Boyd did have the ball in the back after only seven minutes when he latched on to a Burke pass but the linesman raised his flag for offside.
United’s defence had clearly been practising holding their line in training and the Gers players were caught offside another four times before the 20 minute mark to the frustration of the home support.
The Light Blues, however, were to get their noses in front on 22 minutes when Charlie Adam opened the scoring in spectacular style.
Derek Stillie sprinted from his box for no apparent reason to try and clear the danger but his weak kick fell to Adam who curled in a brilliant 40-yard effort into the empty net.
This was a blow to United, who have improved dramatically under new boss Craig Levein, but they reacted well to going behind and had a couple of efforts on goal with debutant Jon Daly coming closest with a shot that flew across goal but went inches wide.
In-form Boyd would have been disappointed not to double his side’s lead when Ferguson played a delightful ball beyond the United defence but the striker skewed his left-foot effort off his marker before being closed down.
With conditions getting worse as the first-half progressed it was almost inevitable that a booking would follow and Svensson was first in Craig Mackay’s notebook with a late challenge on Colin Samuell which put a halt to a swift counter-attack from the visitors.
Ferguson was then unlucky with a free-kick which hit the side netting on 31 minutes but the Light Blues were to double their advantage soon after.
Adam picked the ball up on the left and his exquisite back post cross was missed, somewhat remarkably, by Boyd but Burke was there to nod the ball home from only five yards.
Disappointment was to follow for the home support before the interval when the hard-working Prso pulled up with what looked to be a hamstring injury and he was immediately replaced by Nacho Novo who was to put in a great shift.
With the rain battering down on both sets of players, and most of the fans within Ibrox, the sound of the half-time whistle was clearly a relief to all.
The conditions were to improve slightly for the start of the second period and United came out in the second half-with renewed purpose.
Levein decided to make his first change of the match when he replaced Colin Samuell with Noel Hunt on 51 minutes but within seconds Rangers could have made it three.
When United failed to break dow the Gers’ backline Ferguson picked the ball up midway in his own half before finding Burke who had acres of space on the right wing.
The 23-year-old sprinted into the box but by the time he looked up to see his captain and Boyd alongside him the United defence had had regrouped and Kerr produced a fine tackle.
Rangers were in control at this stage and it was not long before Boyd did his usual and found the net, 58 minutes to be exact.
It was Novo who had space on the right this time and his inch perfect cross found his teammate in the middle and the hitman drilled the ball past Stillie from ten yards.
United were now on their knees and Burke should have made it four but his shot-come-cross did not trouble the busy United keeper and was nowhere near the waiting Boyd.
With the game all but wrapped up, Boydy then scored his second when he got on the end of a fine move.
Ferguson played the ball to Adam on the left and he fed it to Murray who had broke into a forward position.
His cross was perfect for the predator who made no mistake with his low header.
Adam missed a snip on 72 minutes to make it five before Smith made his second substitution by replacing Burke with Filip Sebo.
The Slovakian gave 100 percent as usual but, despite great backing from the home support, was unable to score his third goal for the club.
The script, however, was written for Ferguson to score today and he did so three minutes before the final whistle. Boyd found the midfielder who took the ball around Stillie before finishing with aplomb,
In the end, Rangers could, and probably should, have scored more than five but it was an impressive display from Smith’s troops and the Gers’ fans gave their side a standing ovation after an entertaining afternoon at Ibrox.
RANGERS: McGregor; Hutton, Svensson, Hemdani, Murray, Burke (Sebo 73), Clement, Ferguson, Adam; Prso (Novo 39), Boyd
Subs Not Used: Klos, Papac, Rae, Sebo, Lowing, Lennon
Booked: Svensson (28)
DUNDEE UNITED: Stillie; McCracken, Kenneth, Kerr, Duff, Conway, Cameron (Gomis 81), Robertson, Daly, Dillon, Samuell (Hunt 51)
Subs Not Used: McLean, Archibald, Easton, Watson, Goodwillie
Booked: Kerr (33) Referee: Craig Mackay Attendance: 50,276
Man of the Match: Charlie Adam