Forest began the season solidly enough but Nuno Espirito Santo, who guided it back into Europe with a seventh-placed finish last season, was sacked after a public fall-out with owner Evangelos Marinakis.

Former Tottenham Hotspur manager Postecoglou replaced him but the Australian has won none of his first five games in charge, losing three and drawing two.

Defeat, harsh as it was after Forest created a host of chances, has left it 16th on the table.

"Tough to take. It's another game that got away from us and that has been the story of the last four or five games," Postecoglou said.

"Really disappointing goal to concede and we don't take our chances and that means we don't get the result we wanted.

"We had enough chances to win it or get something out of the game but we have been pretty wasteful in front of goal and that means we have not been able to get the points we need."

Sunderland, meanwhile, is only six games into its first Premier League campaign for nearly a decade but after a this victory, it already has almost half the total amount of points it managed when it was relegated in 2017.

Regis Le Bris's side was among the favourites for the drop after returning to the top flight thanks to a play-off victory over Sheffield United last May.

But under the Frenchman's watchful eye, it has been the surprise package of the season so far, winning three and drawing two of its opening six games to move into the top four with 11 points.

In 2016-2017, the Black Cays managed 24 points, and finished rock bottom of the division.

"It was good to win because it wasn't an easy challenge," Le Bris said. "It was our first away win in the league, so I'm really proud of our fans and our squad because we worked hard."

Omar Alderete's first-half goal was the difference between the two sides at The City Ground with Sunderland mounting a staunch rearguard action as Forest laid siege to its goal.

"They have many threats and are really good on the ball," Le Bris said. "After we scored the first goal, their substitutions added five more attackers but we expected that.

"We defended well with the back five. The players were well connected, they worked hard, and we had a good goalkeeper."