Newcastle United manager John Carver believes that the club's insistence on signing foreign players has adversely affected their Tyne-Wear derby results.
Local-rivals Sunderland recorded a 1-0 win against the Magpies last week thanks to Jermain Defoe's strike.
The defeat was Newcastle's fifth consecutive loss to their fierce rivals, and Carver thinks that the poor run could be linked back to the club's transfer policy.
The Telegraph quotes Carver as saying: "You've got to try and do as much homework as you can and find out about their personality, because we've lost five derby games [in a row]. There's something within the make-up within this group of players.
"And I say within their DNA, that when it comes to a derby game, there's something not right. There's something not right within their make up. No matter how hard you try and no matter what you try and do, it's an issue.
"It's very difficult sometimes because, if you're dealing in the French market or the German market or the Spanish market, then it's very difficult to find out a little bit about their personality, about how they are around the place. It's dead easy if you're dealing with a British club."
Newcastle return to action when they travel to Liverpool on Monday.
