By SABC Sport
30th December 2023
The Red Devils had won the sides' last 11 meetings in all competitions, but new boss Nuno Espirito Santo would celebrate a memorable second win in just five days.
Gibbs-White's super late strike from the edge of the box wrapped up a memorable 2-1 triumph after Marcus Rashford had capitalised on a terrible Matt Turner pass to cancel out Nicolas Dominguez's opener.
This was United's 14th defeat in all competitions this term and a miserable end to the year for a side that were a pale imitation of the one that roared back to beat Aston Villa on Boxing Day.
Match-winner Rasmus Hojlund was absent through illness and Ten Hag's team underperformed at the City Ground, where a forgettable first half made way for a pulsating second period.
Rodriguez fired Forest ahead in the 64th minute, only for under-fire Turner to see a poor pass cut out as Rashford went on to rifle home a 78th-minute leveller.
But the goalkeeper helped make amends four minutes later, denying Christian Eriksen before the hosts raced up the field and Gibbs-White slammed the hosts back ahead.
Turner held firm in stoppage time to ensure Forest beat United at home for the first time since 1992.
INEOS director of sport Sir Dave Brailsford was an interested observer alongside Sir Alex Ferguson on the banks of the Trent, where Kobbie Mainoo heading away an early Dominguez attempt.
Chris Wood, brimming with confidence after his hat-trick at Newcastle on Boxing Day, drove off target before United survived an 11th-minute scare.
Former United talent Anthony Elanga drove a cross in front the left and Raphael Varane's awkward attempt to cut it out took it over helpless Andre Onana and across the face of goal.
The Forest faithful bellowed "you're not famous anymore" as their side continued in the ascendancy, thanks in no small part to United's poor decision making and passing.
The home side crowded out Ten Hag's men in attacking areas, just as they did when Aaron Wan-Bissaka saw a shot blocked shortly after Ryan Yates scooped over at the other end.
A forgettable first half limped on until the break, when Scott McTominay replaced Mainoo.
Ten Hag would also take off Antony in the 54th minute to Forest chants of "what a waste of money" as Amad Diallo made his first United appearance in two years.
A minute later, misfiring United nearly went ahead through the unlikely source of Diogo Dalot. The full-back's first-time drive from distance came back off the right-hand post.
But, in truth, Forest had emerged from half-time with more bite to their play and the City Ground was rocking in the 64th minute.
Elanga played into right-back Gonzalo Montiel, who followed an expert touch with a smart cutback for compatriot Dominguez to stroke a right-footed effort into the bottom corner.
It was an excellent strike that sparked chants of "you're getting sacked in the morning" being aimed at Ten Hag.
Alejandro Garnacho sent an acrobatic effort into the ground and onto the roof of the net as United sought a leveller that Turner was soon relieved not to gift them.
The Forest goalkeeper's miskick flew up in the air but bounced back to him. His blushes would not be spared for long, though.
Turner saw a lax pass out from the back cut out by Garnacho, who squared for Rashford to level in the 78th minute.
Forest fans went ballistic after the goalkeeper's latest error and there were murmurs when he next touched the ball.
But Turner's blushes were spared by stopping Eriksen, sparking a Forest break. Elanga squared for Gibbs-White and the man of the match curled beyond Onana into the bottom corner.
The stadium erupted, just as it did midway through 10 minutes of stoppage time when Turner brilliantly tipped over a deflected Fernandes volley.
Amad was also denied before the final whistle saw players collapse to the turf.