Ruben Amorim wants to keep Kobbie Mainoo and Alejandro Garnacho at Old Trafford, but admitted Manchester United must consider selling academy graduates to stay within the Premier League's spending rules.

Mainoo and Garnacho both impressed in the Europa League win in Bucharest against FCSB on Thursday night, but they have both been linked with a move away during the January transfer window. Mainoo, 19, is set to stay at the club but there is interest from Chelsea and Napoli in 20-year-old Garnacho.

United would have to reluctantly consider offers they view as too good to turn down for the academy gems, with both representing pure profit in accounting terms if they were to be sold. They are also two of the more saleable assets in Amorim's squad.

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Not only do United need to raise funds to reinvest under Amorim, but they remain close to the line on the Premier League's Profit and Sustainability Rules (PSR). Selling academy players, who have no fee to amortise, has become a handy way to boost a club's PSR position and Amorim accepts that United will have to go down that route as well.

"I want players like Kobbie and Garnacho," said Amorim. "The focus is that we have to improve our academy. And you have to bring more [through].

"That is something that all the clubs in England have to take advantage of. The players that come from their academies. To play, to feel the shirt, but also to sell them. So our focus is to bring more [through]."

Garnacho came on at half-time in Bucharest and immediately injected some pace into United's play. Having been in control of the game before the break, they began to create chances in the second period. Garnacho hit the post with the game still goalless before creating the second goal for Mainoo.

The Argentine is on his best run of form under Amorim and beginning to look more comfortable in one of the No.10 roles. He has also knuckled down having been left out of the squad for the Manchester derby in December, along with Marcus Rashford. While Rashford remains out in the cold, Garnacho is now a key figure once again after changing his approach.

"I don't think he is improving [because of] me. He changed right away since that game against City," said Amorim.

"The way he understands things and understands that I just want to help him, I just want to win games. He changed in everything: the approach when you talk with him, the way he recovers.

"He understands that sometimes I am a different coach, that I am demanding in my way and sometimes it is hard, [initially]. Because I am a different kind of coach, a different person, but he understands that it is never in a bad way. It is always for him.

"I think all the merit goes to Garnacho. He is improving and we want to continue to improve with Garnacho. Tonight, he understood the position, the moment when to play inside and outside, the connection with Dalot, that is improving a lot too."

His connection with Mainoo came with both playing in the more advanced roles. That was a shift for Mainoo but his future looks to lie as a No.10, with Amorim honest in his assessment of his struggles to defend in midfield after the game.

He was making just his ninth start under Amorim in Bucharest and the head coach played down the idea the speculation over his future and the lack of progress over a new contract had been destabilising to a player who only made his senior breakthrough last season.

"I don't think it is about his contract," he said. "Everybody in England sees him as a very good player. He played in the European Championship final.

"I think it is more the position. He was not comfortable. Before, he was always playing. Now, he sometimes plays and sometimes not, he wasn’t comfortable but maybe it is something to do with that.

"But I think the key point is the position. It is different for him. It demands a lot from him. Today, in that position, I feel that he was more happy to play. Simple as that. I don't look at the movements, the way he touched the ball. I felt it just watching him. He was so happy on the pitch. That is important for me because if they are happy, they play better. I think he can change position."