Sunderland head coach Dick Advocaat has admitted that he is "unhappy" with the way that his team conceded three goals in their Capital One Cup second-round win over Exeter City on Tuesday night.

Jermain Defoe netted a hat-trick at the Stadium of Light, but it was a nervy half-time interval as the visitors managed to reach the break level on 3-3.

"I am happy with the six goals but I am totally unhappy with the goals we gave away at this level," ESPN quotes Advocaat as saying.

"I don't know if it has to do with concentration or sharpness but they were three crosses and three goals - that's a worry and it's not the first time."

The Black Cats are yet to win a Premier League game this season following two defeats and a draw.