Black Cats boss Keane slapped a £40million price tag on the striker during the transfer window and labelled him "the best striker in the Premier League".
"It's a huge compliment but it will not go to my head.
"I've had a bit of stick for it. And if the manager says something like that about you, you have to put in the performances to escape any b******ings.
"The best in the league is (Arsenal striker Emmanuel) Adebayor right now. But every player has their attributes.
"The manager is not trying to put pressure on any of us. I put pressure on myself to get better - to learn something new in training every day. It's only going to get better. Who knows what I'll be in three years time?"