John Stones to Chelsea: Jose Mourinho in thinly veiled dig at Everton manager Roberto Martinez

Chelsea are pursuing the Toffee's young defender

Everton are determined not to sell Stones this summer (Getty Images)

Jose Mourinho has made a veiled criticism of Roberto Martinez for the Everton manager's outspoken rebuke of Chelsea for their pursuit of John Stones.

Martinez was unhappy with John Terry's comments in praise of Toffees defender Stones, whom the Premier League champions have pursued this summer and had offers rebuffed.

"I'm not speaking about Everton or Stones. I'm just speaking in general," said Chelsea boss Mourinho, speaking ahead of Saturday's season-opener with Swansea at Stamford Bridge.

"If I could, I would speak with you (the media) once in a month.

"And there are other people in football who, if they could, they would have a press conference every day. And I don't want to say anything else."

Chelsea have five first-team defenders and Mourinho is keen to recruit more, with a left-back high on the agenda, but he insists he is not preoccupied by the transfer window.

Another concern is up front. Mourinho is uncertain whether Diego Costa will be fit to begin the Blues' title defence after his troublesome hamstring injury flared up once more, forcing the striker out of last Sunday's Community Shield loss to Arsenal.

"I don't know. I promise you, I don't know," Mourinho said.

"I think he's going to train with the team (on Friday evening).

"His reaction after that and his decision to be confident to play is another story."

Mourinho dismissed the suggestion Chelsea might need to buy another striker due to Costa being an ongoing fitness concern.

"Three is the perfect number and we have three," said Mourinho, who is prepared to field Loic Remy or Radamel Falcao against the Swans.

Put to him he has only two and a half strikers due to the uncertainty surrounding Costa, Mourinho said: "The half when he plays is one and a half, so (that) compensates, because he's a fantastic player.

"I cannot say I don't need him. He's such an important player for us.

"Not just for the goals he scores, but also for the football he produces and also for the mentality he helps to create in the team."

Chelsea are bidding to be the first team since Manchester United in 2008/09 to win back-to-back Premier League titles, a feat Mourinho achieved during his first spell in 2004/05 and 2005/06.

Asked what would constitute success this term, Mourinho said: "I really don't know, because it depends not just about you, it's also about the others.

"You can have a good season and somebody was better than you. And I don't consider that failure. I don't consider that a bad season.

"If somebody was better than you, a little bit better, a couple of points more than you, one goal more than you in a knockout phase, then I don't think it's a failure.

"I just think credit to the others. Let's try to be a good team and let's try to be here in March, April speaking to you about the possibility of winning something."

PA