Leeds keeper Casper Ankergren says he feels Millwall should face punishment for the behaviour of some of their fans in the play-off semi-final, first leg.Millwall fans ran on to the pitch, confronted Ankergren and threw missiles at him after he conceded Neil Harris' winning goal.
"There was something thrown at me, I didn't see what it was as I turned my back on it," Ankergren told BBC Sport.
"It's very bad for football and Millwall should be punished."
Millwall won 1-0 thanks to a goal from substitute Neil Harris and go to a sold-out 37,000-capacity Elland Road in the second leg on Thursday night.
Ankergren added: "I was pushed in the back by one of the fans that came on the pitch too. It should never happen, fans should not be allowed on to the pitch.
"I'm not sure what the security were doing as no-one came to remove them. They are meant to be here to protect the players, it's not good enough.
"Anything could have happened, luckily it didn't and hopefully I wouldn't experience that again.
"English fans are normally much better than Danish fans, who always throw stuff on the pitch and at players.
"But it's happened here at Millwall and I hope something will be done. It is a disgrace to football."
A Scotland Yard spokesman confirmed that one man had been arrested on suspicion of assault.
Leeds manager Simon Grayson admitted it was a hostile atmosphere but felt his players handled it well.
"It's a play-off semi-final, it's hurly burly with a hostile atmosphere and you're going to be on the back foot at times but I thought we defended ever so well," he said.
"I said that if we we're still in the tie after the game today then we can turn it round and we still are in the tie.
"We know now what we've got to do. We've got 90 minutes to turn a 1-0 deficit into a positive for us and we've got players that are capable of doing that.
"We've got 37,000 at Elland Road on Thursday night, which is going to be some atmosphere and that isn't going to get us through the game but it will help."