Jose Mourinho is looking for the final piece of his Chelsea jigsaw and remains determined to secure a new defender during the transfer window.

The Blues saw a £20million bid rejected for Everton’s John Stones last week as the Special One looks to add the finishing touches to his title-winning squad.

Asmir Begovic and loan signing Radamel Falcao are Mourinho’s only summer acquisitions so far but he is hoping three is the magic number for the Premier League champions.

“I am looking for a defender to finish the balance in our squad and after that we are ready to answer to anything that can happen with our players,” he explained.

“If one of our players wants to leave or we agree a deal for a player to leave we have to answer immediately because at this moment we have balance and quality in numbers. We cannot lose that balance.

In the market: Chelsea manager Jose Mourinho during a Press Conference

“To go to next season with basically the same squad that we had last season, when our direct competitors are investing a lot, is a big challenge.

“That’s something I understand and accept - it’s a compliment to us that the other teams are buying so much.

“They will improve immediately with the new players, and for us there is only one way to improve, which is to work fantastically well and to improve what we have which is the same as last season.”

Mourinho has admitted Stones is his preferred choice but Everton manager Roberto Martinez does not want to sell the talented Englishman.

"We made a bid because we like the player, we don't make bids for players we don't like - but I respect Everton. It's up to them - everything is in their hands,” Mourinho added.

"I don't speak about him (Stones) because he's not my player. We've made the bid and the bid is there. Everton have the power to accept or refuse the bid.

Duo: Roberto Martinez is up for the fight of keeping John Stones at Everton

"This is a problem between John Stones and Everton. When the transfer window is open, every club and player is open to bids.

"Bids come for our players and we make bids for other players. The process can be so simple.

"I would advise Roberto Martinez to do the same thing I do. If I don't want to accept any offer, I say 'I don't accept any offer'. He can make it very, very easy.”

Meanwhile, Everton are frustrated that news of the bid has been made public by Chelsea and Martinez has reiterated his stance that the centre-back is not for sale.

"There is the disappointment of a club making a statement to the press and making it openly,” the Spanish supremo answered when quizzed about a bid in Singapore.

"I don't think we'd do it and speak about a player. John Stones is an Everton player, full stop."

Stones said at a sponsor's event on Friday night: "I am very happy at Everton."

John Stones in action during Everton's Asia Trophy defeat by Arsenal in pictures: