Sunderland boss Gus Poyet feels the arrival of Jermain Defoe has already transformed the locker room.

The former Toronto FC striker joined Sunderland yesterday.

Poyet said: "It doesn't happen that way very often, and it's not very often we're in a position where we can bring in a player of the quality of Jermain Defoe.

"But we've got him here, and we have to use him in the right way now. There are no excuses now. I am responsible, and I'm telling you there are no excuses now, so whatever happens from this point onwards is down to me.

"I cannot say one thing one day and then change when it suits me. We were missing something in front of goal, but now we've got Jermain. Now I need to keep him fit and playing, and find a way with Jermain on the pitch to make him score goals. That's my challenge now."