But Gerrard hopes his men will heed his warning and stay clear of such trouble.

He said: "We had a meeting a few weeks back when a couple of the Scottish referees came in and explained the rules of VAR and what the referees and UEFA are clamping down on.

"We've echoed that meeting to the players and made it nice and clear so the players are aware what to do and how to act in certain situations.

"It will be slightly different to what we're used to so everybody has to be ready for that experience, staff included.

"The most important thing that came out of the meeting was to keep playing. There are certain situations when a flag goes up or stays down. In normal situations you might stop or wait, so it's important we play to the end.

"It's important we don't use any gesture of VAR, crowd the referee or go towards the monitor. They've made it very clear they will act and dish out yellow cards.

"One thing for sure, we're going to have to be careful and make sure we behave and we're very disciplined over both legs."

Braga will have to wait until Thursday night to get their first glimpse of Ibrox after Rangers requested they did not train on a pitch that has taken a beating from the Scottish elements in recent weeks.

The Light Blues' weekend clash with Livingston was pushed back 24 hours to Sunday after it was rained off the day before and club bosses are keen to protect it from further damage.

Instead, Braga will be allowed to stage their final preparations at the hosts' Hummel Training Centre – but Gerrard insists there is no sinister motive behind the venue swap.

"For both teams, we want to have the pitch at Ibrox in the best shape it can be in," he said. "It's not a tactic from us. If the pitch was in great condition we'd be more than happy for Braga to use it."

Braga arrive as the form team in Portugal having won eight out of nine games under new boss Ruben Amorim.

His side stunned Rangers' former group-stage opponents Porto to lift the Taca da Liga last month and Saturday's win over Benfica was Os Arcebispos' first triumph at Estadio da Luz in 65 years.

Gerrard's team, on the other hand, have suffered a worrying slip that has seen Celtic open up a 10-point lead at the top of the Ladbrokes Premiership.

But the Rangers boss believes a win on Thursday could be the spark to reignite their campaign.

He said: "I hope so. If we can find that performance against a team at the level of Braga then I'm sure that would bring the belief back.

"I believe that we have found our best performances in Europe. It does seem that the tougher the challenge, the more we rise to it.

"We have nothing but respect for them but we have been the underdogs in this competition throughout the group stages so nothing changes there.

"Without a doubt we're going to have to find a better level than we've managed of late."