Speaking to the media, Rooney said: "I thought in the first half we were okay but the chances they created came from us giving the ball away. I think we tidied up on that.
"I challenged them at half-time to be a bit more aggressive in the final third, to put balls in the box, land on second balls and get shots off. They went out and did it in the second half. That's what you want as a coach, when you're asking them to do things a little bit more.
"They did go out and do it, so I'm really pleased they did.
"In the last 15 minutes of the first half, I think we got control of the game, and we just weren't hurting them enough. The second half started the same way, but with a little bit more tempo, and then we were putting crosses in, getting shots off and that's what the crowd want to see. Then you feel like then Sunderland being a young team, that can affect them.
"I thought in the second half we were outstanding; over the course of the game, I think we deserved to win."