Graeme Souness believes Rangers are five years behind Celtic and thinks there is a distinct possibility Brendan Rodgers' side can go on to win ten titles in a row.

The former Ibrox boss also jumped to the defence of Mark Warburton, who Souness says is working with one hand tied behind his back.

He has urged chairman Dave King to inject fresh investment into the team to strengthen the squad.

Souness was speaking after Rangers suffered their second successive defeat to the Hoops as Moussa Dembele's back-heeled goal sealed their place in the Betfred Cup final.

"Celtic have had the best part of five years to build a gap between themselves and Rangers," Souness told STV.

"That's not to say that it will take Rangers five years to catch them.

"In the next few transfer windows they could buy really well, get lucky with them and catch them very quickly.

"But as a Rangers supporter you have to say that Celtic are a bit ahead right now."

The Hoops have racked up five titles in a row since their rivals' financial implosion.

Souness was asked if ten in a row was a distinct possibility, he said: "I suppose there is, yes, but things in football, like life, change very, very quickly.

"It's not something I would want to contemplate right now and I don't think any Rangers supporter would want to contemplate it.

"They need to buy better players, the owner needs to find money for the manager. I think the manager has done a fabulous job to date."

He added: "I don't think it matters who you get in, there's no such thing as a super coach out there, it's about super players and that is what makes a difference.

"The best coach, the most imaginative coach, the most experienced coach is not going to change Rangers' situation right now, it's about getting better players."

Asked how much it would take to close the gap, he said. "Right now from Champions League money alone Rangers are £30m behind Celtic.

"Having money and spending money is not everything. Of course I would rather have it than not as it gives you a far better chance to be successful.

"And you can only hope in the future that Rangers find some money from somewhere which allows the manager to be competitive.

"Right now he is operating with one hand tied behind his back."