West Ham boss Sam Allardyce admits he does not get along with Chelsea counterpart Rafael Benitez, but insists their ongoing feud will have little impact on Saturday's Premier League clash at Upton Park.
Allardyce and Benitez shared a heated exchange when they were in charge of Blackburn and Liverpool respectively in 2009 when the Spaniard reportedly made a disrespectful gesture toward the Rovers' bench while 2-0 up.
After the match, Benitez mocked Blackburn's style under Allardyce and the now Hammers manager says the issue became "personal", adding "that's why I don't like him and the feeling is probably mutual".
However, Allardyce says the animosity between the pair will have no bearing on Saturday's result.
"There is always a mental battle and I think the bottom line is whatever managers say between themselves, people can construe one way or the other, but it is about your players going out and doing it," he said.
"You can use certain things in what you do prior or during the game and, from my point of view, I always see it as good banter.
"Does it effect players? I don't know. I am not so sure it does. It is one of those things, we can't all get on can we?
"We might not have got on so well over the years, but it is a long time ago and a lot of water under a bridge since then.
"I suppose what he didn't like was getting beaten. It's always been the way, but as far as I am concerned this is the top level, so you can pit your wits against every manager.
"Every manager is different and you will weigh up the tactics they like to play and get yours ready. If you get it right you can upset the big boys, Liverpool were at the time and we managed to upset them."
Allardyce acknowledges Chelsea will still be difficult to defeat, despite their indifferent run of form in recent weeks.
He added: "Chelsea are coming as a fantastic football side that won the FA Cup and the Champions League, so I am more concerned about the players they are going to pick and how they are going to set up and how my team are going to cope with that, than what Rafa's going to say about me.
"It would give me no more satisfaction than beating any other manager - the satisfaction would be fantastic if we can get a result against Chelsea."
Information from the Press Association was used in this report.