New Chelsea chief executive Peter Kenyon has heaped pressure on coach Claudio Ranieri to deliver success but says his position is safe until the end of the season.
Since billionaire Russian Roman Abramovich bought the London club last July, Ranieri's tenure has been the subject of constant rumour with much of the speculation centred on England coach Sven Goran Eriksson.
"The expectations of Chelsea fans at the start of the season, even before we spent £100 million sterling on players, was that we wanted to win something," Kenyon told BBC Television on Sunday. "Spending that amount of money on players just raises that expectation."
Asked if a year without silverware would constitute failure, Kenyon, formerly chief executive at Manchester United, said: "As a football fan, I think you would think that that's a failure."
But he said Chelsea were still fighting on three fronts, the English premier league, FA Cup and Champions League, and that Ranieri was "absolutely" safe until the season's end at least.
"We are not about knee jerk decisions," Kenyon said. "The last thing I want...is the manager or our players looking over their shoulder."
With the arrival of Kenyon as the club's chief executive this week, Ranieri has acknowledged speculation would increase.
"I know very well that when a chief executive changes usually the manager changes," the Italian said at a news conference on Friday. "It's unusual for the previous manager to stay. But I will try to work against the usual story."
Chelsea are third in the league, nine points adrift of leaders Arsenal and seven behind United. Abramovich has spent more than $200 million on new players since taking over.
They play fellow London club Charlton Athletic later on Sunday.
One of Abramovich's first discussions after buying Chelsea was with Eriksson. Newspapers have suggested ever since that the Swede would succeed Ranieri in July after his England side's participation in the European Championship in Portugal.