Aitor Karanka always had "crazy" belief in Middlesbrough revival

Karanka was seen as a high-risk appointment when he replaced Tony Mowbray as manager in October 2013 with the club languishing in 16th place in the Championship.

But the Spaniard will lead his side out against high-flying Chelsea on Sunday with Boro having already proved they belong in the top flight by claiming gutsy points away to Arsenal and Manchester City this season.

Karanka said: "When I came here the team was not in a good way but it felt like I could do something nice here because the chairman, the crowd and the area deserved to be in the Premier League.

"I felt that I could do it, but sometimes I went home thinking I was crazy (thinking) we were going to get promotion - but finally we are in the Premier league. As a manager you can't think long-term. As a player you dream of winning titles or trophies or leagues, but as a manager I never go to my house thinking I can be here in 10 or 15 years, because my only concern now is (the match against) Chelsea."

Boro's clash with Antonio Conte's side is a sell-out but Karanka is keen to play down the particular significance of what will be Chelsea's first visit to Teesside since a 2-0 win in the FA Cup fifth round in 2013.

Karanka added: "To play against Brighton and win promotion is going to be difficult to repeat again - maybe one day if we qualify for the Europa League or the Champions League or if we win a title...

"It's an important game, like Arsenal and Manchester City two weeks ago. We have a lot of games against big teams. It's another big challenge to show we can compete against everybody."

Like Karanka, Conte has found the Premier League a seamless transition and was rumoured to be under pressure before launching into a spectacular run of five straight wins two months ago.

That run - scoring 16 goals and conceding none along the way - has propelled Conte's men to within one point of Premier League leaders Liverpool and made them the new title favourites according to Karanka.

He added: "It's another really tough challenge for us but we've been working hard to play these kinds of games. We know they have scored 16 goals and haven't conceded one goal in those games, but it will be an amazing game to play."

Karanka has a doubt over defender George Friend who suffered a knee injury in training with Brazilian Fabio standing by to replace him in the starting line-up. Dani Ayala is still out with a hamstring strain but Gaston Ramirez is back from suspension.