Rangers turned up the heat after half-time to overcome Dundee United 2-0 in their cinch Premiership clash at Tannadice.
The visitors were well under par in a goalless first half but two strikes in just over two minutes from Fashion Sakala and Malik Tillman soon after the restart eased the nerves and allowed the Gers to see out the game with some control and confidence.
Michael Beale has now won 16 points out of 18 as Light Blues boss since taking over from Giovanni van Bronckhorst in November as his squad becomes stronger by the week.
However, in-form Celtic are still nine points ahead of their bitter rivals at the top of the table, while boasting a vastly superior goal difference, and they remain overwhelming favourites to retain their title.
Liam Fox’s improving United side had lost only one of five games prior to the visit of Rangers and, while they stay second-bottom of the table, they can take some succour from their first-half display.
Beale got the first sight of Antonio Colak since becoming Gers boss, the Croatia striker back for the first time since November 9 after recovering from calf problems.
Jon McLaughlin took over from Allan McGregor in goal with midfielder Ryan Jack in for Glen Kamara, while United striker Tony Watt dropped out for Steven Fletcher, who was back from illness.
The former Hibernian, Wolves and Sunderland forward caught the eye in an otherwise nondescript start to the match, including a shot on the turn from the edge of the box in the 18th minute which flew over the bar.
The visitors had not shown much before that, aside from a Colak drive comfortably saved by United keeper Mark Birighitti.
In the 21st minute Fletcher came close with a volley from a Glenn Middleton cross, albeit referee Steven McLean awarded a corner which appeared to hit the arm of Rangers defender Connor Goldson – subject of a controversial handball penalty incident recently against Celtic which went unpunished – but there was no VAR check.
McLaughlin soon had to deal with a dangerous cross from Middleton with John Lundstram completing the clearance.
United were well-organised and disciplined and a counter-attack in the 41st minute ended with defender Liam Smith curling a shot from the edge of the box just past the post, following a move he had instigated by robbing Colak, who was replaced by Alfredo Morelos for the start of the second half.
Rangers almost took the lead in the 49th minute when Sakala stole in at the back post to reach a Borna Barisic cross but his volley was blocked by Birighitti.
McLaughlin saved another decent drive from Fletcher before the Govan men got the breakthrough in the 54th minute.
Barisic’s pass down the left was flicked on by Jack and Sakala took a steadying touch inside the box before firing high past the Tannadice keeper.
United were still processing the blow when, after Birighitti had made a close-range save from Sakala, Tillman fired rebound into the net from just inside the box and belief was sapped from the home side.
In the 78th minute Gers striker Kemar Roofe replaced Tillman to make his first appearance since October after recovering from injury to give an added boost to the Ibrox outfit.