Forest play Aston Villa in the second-leg of their Europa League semi-final on Thursday, and that clearly influenced Vitor Pereira's selection for his starting XI.
Disastrous run of form for Chelsea
The Blues had slipped down to ninth position in the Premier League table after a disastrous run of form, which had not only seen them lose five English top-flight games in a row, but all had come without them finding the net - something that hadn't happened at the club since 1912.
Only FA Cup games were won during the same period, and that's eventually what saw the hierarchy dispense with Liam Rosenior's services, and replace him until the end of the season with Calum McFarlane.
Forest had seen something of an upturn in form, and before the start of play, had been on a six-game unbeaten run, which included a 5-0 away win at Sunderland's Stadium of Light. Despite this, they still remained only three points above the bottom three.
With Chelsea being unbeaten against their opponents since September 2023, a big performance was required from the Midlands-based outfit for them to emerge victorious.
Great start from Forest
Just a minute and 23 seconds after the kick-off, Forest got off to the best possible start, as Taiwo Awoniyi was allowed the freedom of the Chelsea box to power home a header.
It gave further perspective to the hosts' woes as it was a ninth goal conceded in the first 15 minutes of the first half of games; only Burnley (13) and West Ham (10) have conceded more in the Premier League this season.
Forest's fastest goal of the 2025/26 campaign, it was also important in the sense that the visitors hadn't lost in the current season when taking the lead, and Chelsea had failed to win their last five games when going behind.
Enzo Fernandez's shot against the woodwork was the Blues' first effort of any description in the 10th minute, and just five minutes later, a foul on Awoniyi by Malo Gusto gave Forest a penalty which Igor Jesus coolly dispatched.
The boos from the Chelsea fans towards the board were immediate, loud and long.
The shock of going two goals behind at least sparked a reaction from the home players, but despite having three collective efforts and 76% possession of the ball, they weren't troubling Matz Sels in the Forest goal.
Palmer misses from the spot
Luca Netz's four tackles were a chief reason why the likes of Fernandez and Cole Palmer couldn't break through, along with the industry of Dilane Bakwa (six won duels from eight attempted) and James McAtee (10 one-on-ones attempted).
Chelsea did win a foul right on half-time when Jesse Derry was taken out in mid-air, a collision which saw the Premier League debutant stretchered off and taken to hospital.
When Palmer eventually stepped up to take it, however, Sels guessed the right way, and the West Londoners' search for a goal continued.
A triple substitution at the break from the visitors saw Morgan Gibbs-White come on, and it was he who supplied the assist for Awoniyi to slot home Forest's third with 40 minutes still to play.
One of only four shots on target, their economy was in stark contrast to a Chelsea side for whom finding the net has become a millstone around their collective necks.
Of the 21 shots throughout the game from the Blues, just five were on target.
Lacklustre Blues
It's a problem that Rosenior couldn't sort, and judging by much of the play in this game, McFarlane is unlikely to be able to get to grips with it in the few matches that are left in the season.
With 20 minutes still to play, Chelsea had attempted 19 crosses and were often doing their utmost to remain on the front foot; however, their attacking players, in more general terms, were lacklustre in their work at times and laissez-faire in their attitude.
Indeed, Liam Delap's two off-target efforts were symptomatic of their toil on the day, though oddly enough, Chelsea's passing game was off the charts, with the majority of players posting completion stats of over 90%.
Pretty passing carousels without an end product isn't really a worthwhile exercise, mind you.
Goal of the season from Joao Pedro
A late flurry of pressure from the hosts saw Joao Pedro acrobatically fire in an overhead-kick consolation in the 92nd minute, his 15th of the league season and Chelsea's first goal in 634 minutes in the league.
By then, however, most home fans had already left Stamford Bridge, and so would've missed arguably their team's goal of the season.
With the entire home defence also making just one successful tackle all afternoon, it's clear that McFarlane has got his work cut out if he wants to get Chelsea into Europe next season, which is almost certainly the least expected by the club's owners.
Forest can now consider themselves out of danger, even if mathematically they can be caught, and can turn their attentions to making that Europa League final.
Catch up on the match with Flashscore.
