Sunderland have introduced measures to stop fans of local rivals Newcastle from gaining access to the Stadium of Light as they teeter on the brink of relegation to League One.
With Sunderland six points adrift of safety and only four games left, reports said club officials were concerned that Newcastle fans will attend their remaining home games to cheer on their opponents.
Newcastle do not play on the dates of either of Sunderland's remaining home matches, against Burton and Wolves.
There was no cash admission as Sunderland hosted Norwich on Tuesday, when a 1-1 draw pushed them closer to English football's third tier.
Fans wanting to buy tickets for the remaining games will now have to have a purchase history, showing that they have attended the Stadium of Light before.
Speaking at a news conference ahead of Saturday's crucial trip to Reading, manager Chris Coleman said he understood why the steps had been taken.
"I totally see the security side of it," he said. "I get why. Liaising with the police, you have to listen to them, I understand why because safety has to come first.
"I want to see the stadium with as many Sunderland people as we can fit, but I can understand why the club and the police have come to that decision.
"Football is football, and you're always going to get one team laughing at another, especially if it's two derby teams.
"But all the Newcastle fans I bump in to have been fabulous with me. The proper Newcastle fans have been proper people. They want the derby games back."
Coleman said he wanted his players to prove that they were not abandoning hope of Championship survival, adding: "Our job is to make sure that, at 5 p.m. on Saturday, we're still in the fight and the other teams are looking at it and saying we haven't given it up."