Two goals from Sone Aluko helped Rangers to a victory that ended Dundee United's hopes of denying Motherwell a Champions League qualifying place.
Steven Whittaker curled in a low drive after six minutes before Allan McGregor denied Gary Mackay-Steven an equaliser with a fine save.
Sone Aluko powered past static defenders to fire home twice within 180 seconds to make it 3-0 on 20 minutes.
Jamie Ness on 57 minutes and Alejandro Bedoya in 84 added clinical finishes.
And, although the emphatic win put Rangers eight points clear of Well, it leaves United the same distance behind Stuart McCall's third-top side with only two games remaining.
Salim Kerkar was the surprise choice up front for Rangers along with Aluko, with Andy Little missing through injury and Lee McCulloch only considered fit enough for the bench.
United, unchanged from the side that drew with Hearts, started brightly and a Garry Kenneth free-kick broke through the centre of the defensive wall and Allan McGregor pushed it wide.
From the corner, a Kenneth header across the face of goal was eventually scrambled clear at the back post by Rhys McCabe.
It was McCabe who poked the ball into the path of Whittaker, whose measured grass-cutter curled round a despairing Dusan Pernis and inside the far post from 16 yards.
United were not knocked out of their stride and, when Johnny Russell deflected the ball into the path of Gary Mackay-Steven, only a superb finger-tip save prevented the winger's 15-yard drive finding the net.
Rangers had hardly threatened between the time they opened the scoring and went further ahead.
Kenneth failed to cut out a long ball and, when Kerkar set up Aluko, the striker ghosted past Sean Dillon and fired past Pernis.
A poor John Rankin backpass allowed Kerkar to set Aluko on another run, this time past Kenneth, before driving low into the far corner from 15 yards.
Lee Wallace broke into the United penalty box and only a fine point-blank save from Pernis prevented United being four behind by half-time.
United manager Peter Houston rang the changes at half-time, with youngsters Barry Douglas and Keith Watson on for Kenneth and Mackay-Steven.
The traffic continued towards the United goal, with Aluko forcing Pernis into a near-post save and Maurice Edu mis-hitting straight at the goalkeeper from the resulting corner.
Ness, who had been given a rare start, provided the clinical finish when the ball broke to the midfielder off Aluko after Rangers claimed for handball inside the penalty box.
Edu put substitute Bedoya clear to sidefoot home as Rangers gained revenge for two straight defeats at the hands of the Tannadice outfit.
Live Text Commentary
Full Time The referee signals the end of the game.90:00 +1:48
Willo Flood produces a cross.90:00 +1:09
Unfair challenge on Paul Dixon by Lee McCulloch results in a free kick. Paul Dixon takes the free kick.90:00 +0:25
Free kick awarded for an unfair challenge on Lee Wallace by Keith Watson. Allan McGregor takes the free kick.88:49
Free kick awarded for a foul by Willo Flood on Maurice Edu. Kyle Bartley takes the direct free kick.86:43 Booking
Booking The referee cautions Maurice Edu for unsporting behaviour.86:35
Free kick awarded for an unfair challenge on Willo Flood by Maurice Edu. Robbie Neilson restarts play with the free kick.86:00
The ball is crossed by Kyle Bartley.84:44
Sean Dillon delivers the ball, save by Allan McGregor.83:32
The assist for the goal came from Maurice Edu.83:32 Goal scored
Goal! - Alejandro Bedoya - Rangers 5 - 0 Dundee U Alejandro Bedoya fires in a goal from inside the area to the bottom left corner of the goal. Rangers 5-0 Dundee Utd.82:45
Effort from the edge of the penalty area by Steven Whittaker goes wide of the left-hand post.80:32 Substitution
Substitution Lee McCulloch joins the action as a substitute, replacing Salim Kerkar.78:17
Centre by Kirk Broadfoot, save made by Dusan Pernis.77:35
Free kick awarded for a foul by Lee Wallace on Keith Watson. Robbie Neilson takes the free kick.77:01
Foul by John Rankin on Salim Kerkar, free kick awarded. Direct free kick taken by Maurice Edu.76:01
The ball is crossed by Paul Dixon.75:24 Substitution
Substitution Johnny Russell leaves the field to be replaced by Ryan Dow.74:21 Substitution
Substitution Alejandro Bedoya replaces Sone Aluko.71:15
John Rankin produces a cross, Maurice Edu gets a block in. Outswinging corner taken by Barry Douglas, Lee Wallace manages to make a clearance.
Centre by Carlos Bocanegra.69:34
The offside flag is raised against Johnny Russell. Kirk Broadfoot takes the free kick.68:49
Steven Whittaker delivers the ball, Sean Dillon makes a clearance.67:44
Free kick awarded for an unfair challenge on Salim Kerkar by Sean Dillon. Allan McGregor takes the direct free kick.67:18
Johnny Russell takes a shot. Save by Allan McGregor. Inswinging corner taken from the right by-line by Barry Douglas, save by Allan McGregor.67:09
The ball is sent over by Keith Watson.66:00
Inswinging corner taken left-footed by Barry Douglas from the right by-line to the near post.65:41
Kirk Broadfoot is penalised for a handball. Barry Douglas restarts play with the free kick.65:19
The ball is swung over by Barry Douglas, clearance made by Dorin Goian.64:42
Jon Daly produces a cross, Kirk Broadfoot manages to make a clearance. Corner taken by Barry Douglas, Maurice Edu manages to make a clearance.63:34
Foul by Willo Flood on Maurice Edu, free kick awarded. Maurice Edu restarts play with the free kick.62:16
Johnny Russell sends in a cross, Kyle Bartley gets a block in. Outswinging corner taken by Barry Douglas from the left by-line, Header from close in by Jon Daly misses to the left of the target.61:20
Rhys McCabe concedes a free kick for a foul on Barry Douglas. Free kick taken by Willo Flood.60:48
The assistant referee signals for offside against Barry Douglas. Kyle Bartley restarts play with the free kick.60:03 Substitution
Substitution (Rangers) makes a substitution, with Kirk Broadfoot coming on for Jamie Ness.59:55
The ball is delivered by Scott Robertson, clearance by Kyle Bartley.59:39
A cross is delivered by Jon Daly, Kyle Bartley manages to make a clearance. Scott Robertson produces a cross, clearance by Lee Wallace.57:48
The ball is crossed by Sone Aluko, Scott Robertson makes a clearance.56:51 Goal scored
Goal! - Jamie Ness - Rangers 4 - 0 Dundee U A goal is scored by Jamie Ness from the edge of the penalty area to the bottom right corner of the goal. Rangers 4-0 Dundee Utd.53:06
Willo Flood takes a shot. Kyle Bartley gets a block in.52:51
The ball is swung over by Jon Daly, clearance by Dorin Goian.52:02
Free kick awarded for an unfair challenge on Sone Aluko by Barry Douglas. Steven Whittaker restarts play with the free kick.51:37
Maurice Edu takes a shot. Save made by Dusan Pernis.51:16
Corner from right by-line taken by Rhys McCabe.51:00
Sone Aluko takes a shot. Dusan Pernis makes a save.50:45
Steven Whittaker crosses the ball, Paul Dixon manages to make a clearance.49:10
Keith Watson fouled by Rhys McCabe, the ref awards a free kick. Willo Flood takes the direct free kick.48:14
The ball is crossed by Johnny Russell, save by Allan McGregor.47:18
Unfair challenge on Jon Daly by Kyle Bartley results in a free kick. Paul Dixon crosses the ball from the free kick left-footed from left wing.46:54
Sone Aluko produces a left-footed shot from just outside the box that misses to the right of the net.45:01
The second half begins.45:01 Substitution
Substitution Gary Mackay-Steven leaves the field to be replaced by Barry Douglas.45:01 Substitution
Substitution Keith Watson joins the action as a substitute, replacing Garry Kenneth.45:00 +1:38 Half time
Half Time The players leave the pitch at half time.45:00 +1:11
Corner taken by Gary Mackay-Steven from the left by-line, save by Allan McGregor.45:00 +0:46
Scott Robertson fouled by Jamie Ness, the ref awards a free kick. Free kick crossed by Paul Dixon.44:01
Unfair challenge on John Rankin by Jamie Ness results in a free kick. John Rankin restarts play with the free kick.41:43
The ball is sent over by Steven Whittaker, Paul Dixon gets a block in.41:08
John Rankin gives away a free kick for an unfair challenge on Maurice Edu. Maurice Edu takes the free kick.39:38
The official flags Salim Kerkar offside. Dusan Pernis restarts play with the free kick.38:51
Steven Whittaker sends in a cross.37:26
Corner taken right-footed by Rhys McCabe to the near post, Johnny Russell makes a clearance.36:45
Unfair challenge on Sean Dillon by Sone Aluko results in a free kick. Direct free kick taken by Sean Dillon.36:01
Rhys McCabe takes a shot. Blocked by Gary Mackay-Steven.34:30
The ball is swung over by Steven Whittaker, Salim Kerkar takes a shot. Dusan Pernis makes a save.33:00
Lee Wallace takes a shot. Dusan Pernis makes a save.32:53
The ball is sent over by Dorin Goian.31:55
The ball is crossed by Sone Aluko.31:40
The ball is crossed by Paul Dixon, comfortable save by Allan McGregor.31:24
Gary Mackay-Steven crosses the ball, blocked by Steven Whittaker.30:38
Maurice Edu gives away a free kick for an unfair challenge on Paul Dixon. Paul Dixon takes the direct free kick.30:05
Effort on goal by Steven Whittaker from long range goes harmlessly over the target.28:57
Foul by Sean Dillon on Salim Kerkar, free kick awarded. Rhys McCabe delivers the ball from the free kick right-footed from right channel.27:50
Gary Mackay-Steven fouled by Rhys McCabe, the ref awards a free kick. Free kick crossed left-footed by Paul Dixon, Carlos Bocanegra makes a clearance.26:25
Lee Wallace fouled by Jon Daly, the ref awards a free kick. Allan McGregor takes the free kick.24:42
Kyle Bartley gives away a free kick for an unfair challenge on Johnny Russell. Paul Dixon delivers the ball from the free kick left-footed from left channel.24:12
Jamie Ness produces a cross.22:58
Paul Dixon gives away a free kick for an unfair challenge on Steven Whittaker. Strike comes in from Sone Aluko from the free kick. Inswinging corner taken by Sone Aluko from the right by-line, Dusan Pernis makes a clearance.21:48
The assistant referee flags for offside against Salim Kerkar. Dusan Pernis takes the indirect free kick.20:52
Salim Kerkar takes a shot. Sean Dillon gets a block in.19:35 Goal scored
Goal! - Sone Aluko - Rangers 3 - 0 Dundee U Sone Aluko finds the back of the net with a goal from deep inside the penalty box to the bottom left corner of the goal. Rangers 3-0 Dundee Utd.17:18
Rhys McCabe gives away a free kick for an unfair challenge on Gary Mackay-Steven. Free kick taken by John Rankin.16:18
Salim Kerkar provided the assist for the goal.16:18 Goal scored
Goal! - Sone Aluko - Rangers 2 - 0 Dundee U Sone Aluko grabs a goal from deep inside the penalty box low into the middle of the goal. Rangers 2-0 Dundee Utd.13:44
Rhys McCabe takes a shot. Save made by Dusan Pernis. Inswinging corner taken left-footed by Sone Aluko played to the near post.13:41
Sone Aluko produces a cross.12:25
Outswinging corner taken right-footed by Willo Flood played to the near post, Lee Wallace manages to make a clearance.12:19
The ball is crossed by Paul Dixon, clearance made by Carlos Bocanegra.10:39
Gary Mackay-Steven takes a shot. Save made by Allan McGregor. Corner taken right-footed by Willo Flood to the near post, Dorin Goian manages to make a clearance.7:21
Unfair challenge on Sone Aluko by Sean Dillon results in a free kick. Dorin Goian takes the free kick.6:29
Centre by Johnny Russell, blocked by Kyle Bartley.5:29
Rhys McCabe provided the assist for the goal.5:29 Goal scored
Goal! - Steven Whittaker - Rangers 1 - 0 Dundee U Steven Whittaker gets on the score sheet with a goal from the edge of the area to the bottom left corner of the goal. Rangers 1-0 Dundee Utd.0:55
Dorin Goian challenges Jon Daly unfairly and gives away a free kick. Direct strike on goal from the free kick comes in from Garry Kenneth, Corner taken by Gary Mackay-Steven from the right by-line. Save by Allan McGregor.0:00
The referee starts the match.
Live data and text provided by our data suppliers