A steward was taken to hospital after being trampled by a horse during a pitch invasion at the end of Preston North End's Capital One Cup win over local rivals Blackpool.
Shortly after Tom Clarke's late winner in the 1-0 first-round victory at Deepdale, the final whistle prompted some of the home fans to run on to the field. As stewards attempted to help clear the pitch, one was knocked down by a police horse and then struck by another while on the ground.
The steward was subsequently seen walking away from the incident, but a Preston spokesman later confirmed they had been taken to hospital.
"A steward was injured by a police horse," the spokesman told BBC Sport. "He suffered damage to his shoulder, and has gone for an X-ray."
Blackpool manager Paul Ince was furious with the lack of control for the local derby, and said he feared it might take a tragic incident to occur before decisive action is taken.
"This is the problem in football and we talk about the respect campaign and you see enough incidents in football where fans are allowed to run on the pitch," he said.
"We've seen goalkeepers get hit and players get punched. When are we going to learn?
"When you've got 200 Preston fans running on the pitch and my players are still on the pitch, who knows? There's no control and is it going to take someone getting stabbed before we wake up and smell the coffee?
"This is a big derby, is there enough stewarding in the ground?
"We'll have to wait for something to happen to do something about it. There have been enough incidents over the last two or three years that we really should be getting our heads together about it."