Middlesbrough head coach Aitor Karanka has admitted that Sunderland striker Jermain Defoe is a "dangerous player".
Karanka is currently preparing his side for their first clash with their North-East rivals since 2012 and he has acknowledged that his team must cope with Defoe, who started the season with a goal at Manchester City last weekend.
The Spaniard told reporters: "It's difficult to stop him because he's the kind of player, when you're always behind him it's easy to mark him but, I don't know why, he scores every single week.
"So for that reason it's going to be difficult. We have to keep our concentration for 95 minutes because he's the kind of player who, if you miss your concentration for one second, he'll take advantage. He's a really dangerous player."
Middlesbrough began the new campaign with a 1-1 draw at home to Stoke City.
