Chelsea interim manager Rafael Benitez has reminded Neil Warnock that Sheffield United's relegation from the Barclays Premier League was not decided by one match alone.
Leeds boss Warnock is unsure whether he will shake Benitez's hand before Wednesday's Capital One Cup quarter-final due to a dispute between the two dating back to 2007 when the Blues boss Benitez selected what Warnock perceived to be a weakened team in Liverpool's penultimate game of the season against Fulham - which Fulham won and United were relegated.
The Spaniard is willing to shake hands in an effort to avoid controversy, but said: "Every person has their ideas of each other. I'm professional and will try to do my job and won't be involved in anything, but what I will say is that the league is 38 games and not just one match."
He added: "I'm professional so I won't have any problem (shaking Warnock's hand). There will be a lot of people watching us, so we have to behave.
"I saw that he said he has an email from me threatening to sue him, but I don't remember. It's true, but I didn't remember it.
"I will concentrate on my job and hopefully we can talk about football, which is best for the fans and everyone. We need to leave things on the pitch."
If Warnock exacts the revenge he craves at Elland Road on Wednesday night, Chelsea will have been denied a fifth piece of silverware this season following Sunday's defeat by Corinthians in the Club World Cup final.
The jet-lagged Blues arrived back from Japan on Monday afternoon and depart for Yorkshire on Wednesday, continuing a hectic schedule that means Leeds will be Benitez' eighth game in charge since taking over 25 days ago.
Chelsea's playing resources have been stretched by the loss of John Obi Mikel, Gary Cahill and Ramires to suspension and while striker Daniel Sturridge may return from his hamstring injury, John Terry is still struggling with the knee problem sustained against Liverpool on November 11.
The outlook on Terry is concerning with Benitez reluctant to offer a return date for Chelsea's captain, revealing only that his rehabilitation is proving unpredictable. Frank Lampard will start at Elland Road.