Sunderland manager Dick Advocaat has urged Sebastian Coates to be more confident on the pitch as he bids to improve the team's fortunes.

Much like his defensive teammates, Coates has struggled to find his form in the early stages of the campaign, and Advocaat believes that the Uruguayan needs a different frame of mind.

"Coates did really well in the last six games of last season," the Black Cats boss told reporters. "But I told him yesterday that he needs to be sharper.

"He is a little bit shy and that's not possible.

"We saw against Bournemouth that he became better as the game went on, but what was he doing at the start?"

Coates played 90 minutes as Sunderland lost 4-1 to Manchester City in the third round of the League Cup on Tuesday night.