Head coach Dick Advocaat has warned his Sunderland side to tighten up in defence after they shipped three goals in their Capital One Cup second-round win at home to League Two Exeter City.

A Jermain Defoe hat-trick ensured that the Black Cats eventually saw off the Grecians 6-3 at the Stadium of Light, with the win setting up a meeting on Wearside with Manchester City in the third round.

However, veteran Dutch boss Advocaat was far from satisfied with what he saw, with his side having conceded 11 goals in four games so far this season.

He admitted: “I’m happy with the six goals, but totally unhappy with the way we gave three goals away. That has to improve and the players know that.

“I never had the feeling they would beat us, but I am still concerned about how we gave the chances away.”

The positive for Advocaat was another goalscoring display from former England striker Defoe, who has now netted five times in four appearances this term, with his treble against Exeter added to strikes against both Leicester City and Swansea City.

Defoe can be backed at 7.50 to be the first goalscorer on Saturday when Sunderland head to the West Midlands to take on Aston Villa, while he is 3.25 to score at any time.

However, the Black Cats may have to make the trip without Scotland international frontman Steven Fletcher, who lasted just nine minutes against the Grecians before being forced off with a knock.

Fletcher was introduced at half-time in place of Danny Graham, but soon had to give way to Duncan Watmore, who scored the fifth goal for the home side.