Sports Direct have been granted an interim injunction that could delay Rangers selling the club's new strips.
The retail group, owned by Newcastle owner and former Ibrox shareholder Mike Ashley, allege that a deal between the two parties has been breached.
Ashley and the Rangers chairman Dave King negotiated new terms last June at a cost of £3m to the club.
That agreement is due to expire and Rangers want to conclude a deal with another retailer.
Rangers announced a new three-year kit deal with Hummel in April. The strips were unveiled last week although there was no indication when they would be available for fans to buy.
Sports Direct (SDRI) argue they should have been given the opportunity to match "some or all" of a third-party offer to sell merchandise.
The matter will be dealt with again on Tuesday.
After a hearing at the High Court of Justice on Monday, Mr Justice Bryan's decision said: "Broadly the present dispute arises out of a retail operations distribution and IP licence agreement, dated 21 June 2017 between SDIR and Rangers. Under that agreement SDIR sells Rangers replica kit, as well as other Rangers branded products such as clothes at the Ibrox Stadium, through operating the Rangers Megastore and also through SDIR's retail shops and online.
"The application is made on short notice for interim injunctive relief, which arises out of statements that have been made by Rangers that it will, as soon as practicable after 4 July enter into an agreement with a third party that has made an offer for the provision of services, such services to be provided after the expiry of the Agreement, in what is said, or alleged by the claimant, to be breach of the contractual obligation of Rangers to give SDIR an opportunity to match some or all of that third party's offer, the "matching right".
"It is said that if Rangers is not restrained from doing so by this court its actions will thereby wrongly deny SDIR the opportunity to continue to provide some or all of the services to Rangers after the expiry of the initial term."
As part of a witness statement, Rangers secretary James Blair said: "Being able to market a new football strip for the start of the season is essential to maximise impact and sales."
Mr Justice Bryan's decision continued: "It is said that if that opportunity is missed there will be a loss of income and of cash-flow, which impacts upon the ability to bring in players in the transfer window in August and, hence, on on-field performance which, in turn, impacts upon prize money."
Sports Direct say Rangers are obliged to provide a more detailed breakdown of the third party offer.
Rangers lawyers told the court: "The Notice of Offer sent on 4 June was valid and complied with the requirements of the retail agreement. It was also made clear that it was said to be vital to Rangers' business model for the next and following seasons for it to launch its retail operations from 1 August, four days before its first fixture and to be able to do so it required to conclude a deal with the offeror as soon as practicable after the 10 day business period from 20 June expires."