London - Manchester City manager Manuel Pellegrini risked angering Chelsea counterpart Jose Mourinho on Friday by insisting banned Blues striker Diego Costa needs to change his game.
Chelsea forward Costa has been ruled out of Premier League leaders Chelsea's top-of-the-table clash with City at Stamford Bridge on Saturday after being hit with a three-match ban Friday.
The Spain international was suspended after being found guilty of a Football Association charge of violent conduct for stamping on Liverpool's Emre Can during Tuesday's League Cup semi-final second leg at Stamford Bridge, which Chelsea won 1-0 to complete a 2-1 aggregate victory.
Pellegrini, asked for his views on Costa's ban during a news conference in Manchester on Friday, said: "He is a great player, a very important player.
"He has his character, it is not an easy character, but I hope for him that (with) this punishment - and I am not trying to take advantage for the game tomorrow - it will be a good thing for him to change in the future because he doesn't need to do it in that way because he is a very good player, a top player."
The Chilean's comments were not set to receive a quick answer, in public at least, from Mourinho as the Portuguese cancelled on Thursday his regular pre-match press conference, due to be held Friday, amid suggestions the Chelsea boss did not want to answer questions about Costa.
Meanwhile, Pellegrini was reluctant to say anything else about Chelsea, amid concerns he might provoke Mourinho further - although it would be no surprise if the Chelsea boss took offence at his remarks regarding Costa.
After the sides drew 1-1 at the in September, Pellegrini compared Mourinho's men to Stoke, saying they too were a "small team" trying to defend.
That prompted Mourinho to respond by saying: "Many times he says he doesn't speak about me or my team but he continues to do so."
It was, therefore, understandable when Pellegrini said Friday: "I don't talk about Mourinho."
Chelsea will kick-off on Saturday with a five-point lead over second-placed City, the reigning champions, but Pellegrini rejected suggestions that this weekend's clash was a 'must-win' game for his side.
"I think it is a very important game. It is not the game that will decide the title because after that we have to play for 45 points more," he said.
"If you remember some years ago this club won the title after being eight points behind Manchester United, so in football you never know."
While Chelsea will be without Costa, City will also be missing a key player as midfielder Yaya Toure is with the Ivory Coast at the ongoing Africa Cup of Nations.
City have not won any of the four league games the 31-year-old Toure has missed this season and were knocked out of the FA Cup in his absence last week.
However, Pellegrini said: "I say always the same thing, in this case for Diego Costa or Yaya, big teams with important squads cannot depend on just one player."
Saturday's match is also set to see City midfielder Frank Lampard return to Stamford Bridge for the first time since leaving Chelsea.
Lampard is the London club's record goalscorer and he once said he would not play for a rival Premier League side.
But the 36-year-old's move to US Major League Soccer team New York City has been delayed by the decision of 'sister club' Manchester City to extend his loan spell at the Etihad.
Lampard came off the bench to score City's equaliser against Chelsea in September, but did not celebrate.
Asked what sort of reception Lampard would receive on his return to west London, Pellegrini said: "I am sure that Frank Lampard will receive the best reception from their fans that they can do. He is a top player, maybe the most important in their history."
As for a possible Lampard goal celebration, should he score on Saturday, Pellegrini added: "First I prefer him to score the goal. After that we will see if he celebrates or if he doesn't celebrate.
"If he scores, I celebrate."