JJB Sports has bought a 10.1% stake in sportswear firm Umbro in a move to protect its stake in the market for England football shirts.
Umbro has been the target of an unnamed suitor
Reports a day earlier said an unnamed suitor had targeted Umbro, sending its shares 27.5% higher.
The newly-acquired 10.1% stake, plus Sport Direct's existing 15% stake in Umbro, mean any suitor would have a tougher battle ahead, say analysts.
By Friday's close of trade, Umbro shares had risen by 13%.
Umbro has suffered in the wake of poor performance from the England team.
Hopes of a trading recovery are slipping as the chances of England qualifying for the 2008 European Championships drop.
On Thursday, Reuters said sources close to the matter named competitor Nike as the suitor for Umbro. The US firm would not comment on what it called "speculation".
The sportswear market has consolidated since Adidas bought Reebok in 2005.
Adidas is now the subject of takeover rumours while French retailer PPR has built up a large stake in German sportswear firm Puma.
Umbro confirmed it had received an approach but said that it "may or may not lead to an offer being made" for the firm.
As well as providing kit for the England team, Umbro also supplies the kit for six Premier League clubs.