Frank Lampard has warned Chelsea's foreign legion not to underestimate Leeds as the old enemies prepare to renew their long and bitter rivalry in the League Cup quarter-finals.
Lampard is one of the few players in Rafael Benitez's squad with experience of the bitter nature of clashes between Chelsea and Leeds as the clubs haven't met since 2004.
And the England midfielder has been quick to point out to Chelsea's numerous overseas signings that a visit to Elland Road in the League Cup quarter-finals on Wednesday is more than just any old fixture.
Leeds may be stuck in mid-table in the Championship at present but, under fiery boss Neil Warnock, Lampard knows they are sure to be up for a match that brings back memories of a ferocious rivalry born in the 1970s when both teams were regularly competing for silverware.
The most infamous meeting between the clubs, who are often regarded as emblematic of the cultural divide between the north and south of England, came in 1970 when Chelsea won a brutal FA Cup final replay at Old Trafford.
"There's a rivalry, we're aware of it and we have to play on the pitch with passion and do the physical side of things up there, because they're going to be right at it," Lampard said.
"We can't expect to go up there and tap it around and get a result. We have to do both sides."
Spain winger Juan Mata, who moved to Stamford Bridge at the start of last season, added: "Lampard told me about the rivalry. He told me the Seventies was when it started.
"They are always difficult games, competitive between supporters. We just want to play and, if it is possible, to win."
As well as coping with fired up Leeds, Chelsea must somehow lift themselves physically and mentally from their gruelling trip to Japan, where they were beaten in the Club World Cup final by Brazilian side Corinthians on Sunday.
Lampard, who captained Chelsea in Japan in the absence of the injured John Terry, admits the Blues have plenty of room for improvement after a traumatic season marred by the sacking of boss Roberto Di Matteo and an early exit from the Champions League.
"You can't go and win every tournament every year. We've never done that. No-one does it," he said.
"We've changed the personnel a bit this year and there's been a bedding-in process and we've changed the manager, so there's been quite a few circumstances this year.
"We just have to try to improve and play better, simple as that.
"Win this match and we're in the semi-final and with the possibility of a decent draw."