Giovanni van Bronckhorst says Rangers must "respect the decision" of the referee after his side drew at Dundee United to lose ground on Scottish Premiership leaders Celtic.

Ross Graham - who headed United's first-half opener - survived two penalty calls against him.

"What can we do? There is no VAR," Van Bronckhorst told Sky Sports.

• Reaction & as it happened

Rangers, who are yet to win away from home in the league in 2022, benefitted from two VAR decisions in Thursday's 4-2 Europa League win away to Borussia Dortmund, including a first-half penalty.

"VAR will make it easier," said Van Bronckhorst. "These decisions that can be turning points, they can change the game but there's no VAR so end of discussion.

"Every decision that the referee will make, it cannot be overturned, so we have to respect the decision he makes."

Thomas Courts' United end the weekend fifth, in between Hibernian and Motherwell, with all three sides on the same points.

In a breathless encounter, Rangers' calls for a handball inside the United box were turned down after Charlie Mulgrew's clearance connected with Graham's outstretched arm. Referee Bobby Madden allowed play to continue but replays suggested the visitors had a case.

Alfredo Morelos was then played in by Scott Arfield at the end of a swift counter-attack but could not get a shot away before goalkeeper Benjamin Siegrist gathered.

Ilmari Niskanen sold three Rangers players a dummy and was only denied a goal by a James Tavernier deflection that took the ball inches wide.

The hosts grew in confidence and began to win corners, which proved to be Rangers' undoing. Dylan Levitt crossed from the left and Graham outjumped Filip Helander to beat Allan McGregor. It was an early birthday present for the defender, who turns 21 on Wednesday.

United maintained their intensity early in the second period and Marc McNulty tested McGregor from Niskanen's low cross.

Tavernier's corner was headed powerfully towards goal by Aribo but Siegrist was alert with the save. Substitute Fashion Sakala claimed to have had his shirt tugged by Graham as he tried to score on the rebound.

Sakala improved Rangers as an attacking threat and his two low crosses in quick succession from the right could not be converted by Morelos, Siegrist saving the second chance.

On the other flank, Ryan Kent escaped his man and pressed with the final delivery inches away from the sliding Morelos.

But Rangers' incessant pressure in the final half hour told when Kent's pass released Calvin Bassey to the byeline and his low ball back was battered high into the net by Aribo.

Amad Diallo had joined the visiting attack and almost scored when put through by Kent's lob, his effort rattling the right-hand post. Kent retrieved possession and set up Ryan Jack but Mulgrew's superb block averted the danger.

Sakala and Kent were off target with further efforts and Siegrist and Sakala needed treatment after they collided in added time.

There was one more nervous moment for Siegrist when another fierce Sakala cross clipped the crossbar.

Man of the match - Ilmari Niskanen

The winger (far right) was a persistent pest to the Rangers defence and unfortunate not to score

What did we learn?

Dundee United have been a thorn in Rangers' side this season, having beaten them once already this term, and Courts clearly saw an avenue from set-pieces that his side exploited.

Though many would argue Rangers created enough chances to win, the home side brought a lot to the game and were good value for their point.

Rangers, without injured January signing Aaron Ramsey, continue to struggle on the road domestically with points now dropped away to Aberdeen, Ross County, Celtic and Dundee United since the winter break.

However, the fight they showed in the second half suggests they are not done with the title race.

What did they say?

Dundee United head coach Thomas Courts: "It was a rollercoaster of emotions. Once you get the breakthrough, that helps the game-plan. The boys were really tactically astute, very disciplined on the pitch. We more than merited any stroke of luck that we got and a draw was probably a fair result.

"Second half, Rangers are going to try and find their way back into the game with the quality that they have and the alterations that the manager made. When Rangers got the breakthrough, it probably was something that they deserved."

Rangers manager Giovanni van Bronckhorst told Sky Sports: "Disappointment that we did win. I don't how many chances we created - I think the most chances we created this season to score. The chances have to be scored and that's what didn't do and that's why we lost points."

What's next?

Rangers play the return leg of their Europa League tie with Borussia Dortmund at Ibrox on Thursday (20:00 GMT). Dundee United visit Aberdeen in the Scottish Premiership on Saturday (15:00).