NOTTINGHAM, England -- Anthony Elanga chose a muted celebration after his wonderful solo goal against Manchester United, but the smile that crept over his face gave away the quiet satisfaction of scoring against his former club.

Who could blame him? Man United decided Elanga wasn't good enough when he was allowed to move to Nottingham Forest. A key part of manager Nuno Espirito Santo's revolution at the City Ground, he'll probably be playing in the Champions League next season.

Forest's 1-0 win over United -- earned thanks to Elanga, their flying Swedish winger -- cemented their place in the Premier League's top four. After a 13th league defeat of the season, Elanga's former Man United teammates are facing the prospect of finishing the season in the bottom half of the table for the first time since 1990.

"All you want to do is keep on improving, coming here is about playing and developing," Elanga told TNT Sports after helping Forest to their first league double over United in more than 30 years. "I appreciate Manchester United so much as I learned a lot there. I am enjoying my football and I want to keep on going."

It's players like Elanga who show just how hard it will be for manager Ruben Amorim to turn United around. It's not just about finding good players -- it's about finding players who are able to thrive at United.

"In Manchester United, you don't have the time," said Amorim, when asked about Elanga's impact at Forest. "I will not have the time. We have to get it right fast. You are not talking about players that didn't play for Manchester United. They were here playing for Manchester United. Here, the pressure is too big sometimes."

There was barely any dissent from supporters when Elanga moved to Forest for 15 million in 2023. If anything, it was viewed as a good deal for an academy graduate who had been at the club since the age of 12.

But away from the glare of the Old Trafford spotlight, he's flourished. His goal against United was his sixth in the league this season. It was by far his best. After picking up the ball deep in Forest's half, his explosive pace took him 85 metres in under nine seconds. After that, he still had the strength to shrug off Alejandro Garnacho and the calmness of mind to coolly pass his finish into the net.

"It is about attacking the space and getting to the opposite goal as quickly as I can," said Elanga. "I saw the space and I believe I'm one of the fastest players in the league. The finish is something I have been trying to work on. Left foot or right foot, I am quite comfortable with both feet this season."

It was the type of thrilling attacking play that United fans have missed for a while. Most would probably gladly have Elanga back in the squad, particularly after watching Garnacho have a miserable game against Forest in which he was wasteful with his passing and shooting.

Elanga's step up since leaving United isn't isolated. Marcus Rashford has looked a better player at Aston Villa and, after scoring twice against Preston North End on Sunday, is preparing to play in the Champions League quarterfinals next week. Antony, who left on loan in January with Rashford, has impressed at Real Betis.

"We are we are talking about a lot of players that come from Manchester United and they are doing right, but they had the chance here," said Amorim. "Sometimes you don't have time and you should have time for these kids to develop, but for that you need a strong base to support all these kids.

"If you don't have that strong base, we are not going to help our kids. So they had their chances and sometimes football is like that, the pressure of playing from Manchester United is really big."

Decisions on Elanga, Rashford and Antony aren't necessarily mistakes, but they do provide a warning for Amorim ahead of a summer in which he will hope to make wholesale changes.

New signings come with a risk -- particularly at United -- and it's damning that of all the players who have come through the door since the last title in 2013, only Bruno Fernandes is considered a successful investment. That needs to change quickly if United are going to challenge for the Premier League again.

Fernandes is still comfortably United's best player. He had an off night against Forest and the result was that Amorim's team created very little.

Despite facing 23 shots, Matz Sels didn't have much to do to keep his 13th clean sheet in the league this season. Diogo Dalot hit the crossbar with a looping header in the first half and Murillo cleared Harry Maguire's bundled shot off the line in the last minute of stoppage time. That was about all United had to show for nearly 70 percent of possession.

"We created some chances but we could create more with the possession that we had, we reached the final third a lot of times," said Amorim. "We need to be better in that final third because that is really important to score goals and you have a lack of those. In the final third, we were not good enough."

United defended well and dominated the ball, but it was only when Maguire was thrown on as an emergency centre forward that they looked consistently dangerous.

It was more proof, if any was needed, that adding goals to the squad in the summer will be vital to Amorim's hopes of making a step forward next season.

That, though, will require making the right decision on the right player at the right time. And as Elanga has shown since making the move to Forest, it's easier said than done.