AITOR KARANKA has admitted Stewart Downing was replaced at half-time on merit rather than for an injury as Middlesbrough slipped to a defeat at home to Nottingham Forest.

Downing, like a number of his team-mates, had a frustrating afternoon in the No 10 role against Forest and Karanka decided to bring on Adam Forshaw rather than switch his position.

The substitution of the homegrown talent signed from West Ham in the summer caused something of a stir but there was no suggestion that it was because he had picked up a knock.

Karanka said: "When I think a player's not performing well I have to substitute him. Today it was Stewart. I have to try to do the best sometimes I'm right and sometimes I'm wrong.”

He added: "We needed more intensity and tempo on the pitch. Forshaw is the type of player you can trust 100 per cent but it didn't work. We've lost two games but we're still in the top two.”

Forest struck the winner with 20 minutes from time through Jamie Ward and Middlesbrough struggled to create chances, so slipped to back to back defeats for the first time in approaching two years.

It also means Middlesbrough have dropped behind new leaders Hull City and Karanka wants everyone to blame him rather than anyone else for the performance and result.

He said: “We've had a lot of teams who've defended a lot more than Forest. They were really organised and they're now 12 games unbeaten. They came here to play they did really well on the counter-attacks and they scored. Today it was more my fault than the other team.”

He added: "Losing at home is disappointing but it's not just the game today it's the last three games now. They have been really poor. We have two weeks to work in the office and two weeks to work on the training pitch. We've lost two games but we're still in the top two and I'm really optimistic.

"I know the reason for the problem but I prefer to fix it in the training ground. I know the reason and I can fix it. The problem is when you're in a bad run and don't know why but I know the reason.”

Boro full-back George Friend left the Riverside with his arm in a sling after falling awkwardly and heavily on his shoulder. He will be assessed and will have a scan to determine the extent of the problem.