Teenager Josh Acheampong headed the visitors ahead early in the second half before Pedro Neto curled home from a free-kick, totally changing the complexion of the match.

Postecoglou, sacked by Tottenham in June, is now winless at Forest in eight games in all competitions, which will further test the patience of owner Evangelos Marinakis.

Forest, who started the day just one point above the relegation zone, had a series of chances to take the lead in the first half, thanks largely to a sloppy defensive display by Chelsea.

But they failed to capitalise and Enzo Maresca's men grew stronger as the match wore on.

Chelsea were without a long list of first-team players including Cole Palmer, Benoit Badiashile and Enzo Fernandez, while Moises Caicedo started the game on the bench.

Maresca was forced to watch from the stands at the City Ground after being sent off for his wild celebrations in his team's win against Liverpool before the international break.

- Forest chances -

Elliot Anderson had an early opportunity to put Forest ahead but chose not to shoot with his left foot when in a dangerous position and was dispossessed when he turned inside.

Morgan Gibbs-White drove over from outside the box and had a chance at the far post moments later but could not get over the high ball.

Chelsea themselves had an opportunity to take the lead shortly before half-time but Andrey Santos skewed his shot narrowly wide after Joao Pedro flicked the ball over the top, leaving Maresca with his head in his hands.

Pedro Neto drove over as Chelsea finished the first half strongly.

Maresca made a triple change at the break, bringing on Caicedo, Jamie Gittens and Marc Guiu and it reaped early rewards.

The visitors took the lead when Neto sent in an inviting cross for defender Acheampong, who headed home for his first senior goal in the 49th minute.

Three minutes later Chelsea doubled their lead when Neto curled his free-kick around the wall of red shirts, past the despairing dive of Matz Sels.

Forest had a chance to pull a goal back just after the hour mark but Neco Williams blazed over from close range and Chelsea goalkeeper Robert Sanchez did well to keep out a header from Nikola Milenkovic.

Forest substitute Igor Jesus went agonisingly close to pulling a goal back when his shot on the stretch hit the underside of the bar and bounced down onto the post.

Chelsea captain Reece James scored late to make it 3-0 on his 200th appearance for the club, firing home from near the penalty spot after the ball dropped to him following a corner.

That sparked a mass evacuation from the City Ground, leaving Postecoglou pensive on the touchline.

Chelsea's Malo Gusto was sent off for a second yellow card in the latest display of ill-discipline from the young team but victory lifted them to fourth in the table, just two points behind leaders Arsenal.

Postecoglou was defiant at his pre-match press conference on Friday, saying if he is given time at a club it always ends "with me and a trophy".

But chances are running out for the Australian to turn things around at Forest, who finished seventh last season under then manager Nuno Espirito Santo.

Former Burnley and Everton manager Sean Dyche is reportedly in the frame to replace Postecoglou.

Marinakis's seat was empty with a quarter of the match to play, in a potentially ominous sign for the Forest boss.