Sunderland thought they had levelled seven minutes after the restart when Emanuele Giaccherini fired home from Steven Fletcher's knock-down, but a harsh offside flag ended his celebrations.
Gus Poyet: "It was a very difficult day for me today.
"I need to be careful with what I say because it could bring consequences, so I am going to say very little. Sorry about that, but I think it is best.
"I think you want to see me here every week, so I would prefer to keep it short. There is disappointment of course, I didn't expect that.
"It could be a good excuse, that the referee [Mike Jones] was poor. He didn't let us play when we needed to, he stopped the game a hundred times, he talked to everybody - the only thing missing was him making a phone call.
"And then the linesman - normally it should be very difficult for a person 50 yards away to see a 5'6" player behind a 6'2" defender. Incredible.
"He probably saw the top of his hand and gave him offside. That is the excuse of the day today.
"The linesman did something we were not expecting. Sometimes these things go for you, today it went against us. If you want an excuse, you get one."