Aitor Karanka (left) and Jose Mourinho pictured together at Real Madrid

Aitor Karanka took time out of Middlesbrough's preparations for their Capital One Cup clash at Manchester United on Wednesday night to offer his support to Jose Mourinho.

The Boro boss, who spent three years as Mourinho's assistant at Real Madrid, said he phoned his close friend after Chelsea's defeat at West Ham on Saturday.

Mourinho's side languish 15th in the Premier League after losing half their matches this season, while former Porto manager was hit with another misconduct charge by the Football Association after being sent to the stands by referee Jon Moss at the weekend.

Chelsea manager Jose Mourinho (right) was sent to the stands during his side's defeat to West Ham

"He's [Mourinho] not good because he's a winner and when he's not winning, he's not good. But I think his friends have to be here to support him," Karanka said.

"When he was winning trophies, the Champions League and the league, everybody was saying how good he is. Now his friends are the people who have to say he's the best and is going to keep on being the best."

Karanka added: "I'm sure with his knowledge and players and staff he will be successful really soon.

"He's the best and the strongest and I'm sure he will be successful again. All the focus is on him now and you have to learn every single day and keep going.

"He has very good staff and very good players and I'm sure the group will help him a lot. I want to wish him all the best."

Highlights of the Sky Bet Championship match between Wolves and Middlesbrough Highlights of the Sky Bet Championship match between Wolves and Middlesbrough

Karanka has enjoyed mixed success against Premier League opposition in cup competition, with his side losing 14-13 on penalties at Liverpool in last season's League Cup before beating Manchester City in the FA Cup at the Etihad Stadium in January.

The Middlesbrough boss said he would be sending out his strongest possible side at Old Trafford, but would still be without key players for the fourth-round tie including Adam Forshaw and winger Albert Adomah.

However, there could be a place in his squad for Bruno Zuculini, a recent loan signing from Manchester City.

Middlesbrough manager Aitor Karanka backed Jose Mourinho to turn things round at Chelsea

Boro will be followed by 10,000 supporters to the game at Old Trafford and Karanka said these kind of matches were for the fans.

"They deserve these games. I want to express my gratitude because they are always with us. At Old Trafford, in Cardiff at Blackpool last season," he said.

"I'm really proud of them and hopefully we can show them a really good performance."