Both midfielders have battled to find consistency since joining United.
Raiola told the Daily Mail: "It's true Pogba is not playing his best yet, he is taking time to adjust but people don't always see the bigger picture. He will dominate for 10 years. He is United's lost son.
"Mkhi was the best player in the German league the last two seasons. He has a strong mentality and will be an asset once fully fit.
"Sometimes it is better to lose because you realise you are not what you thought. I still think United will win the league though as they now have the quality."