Brazilian Anderson has been granted a work permit by the Home Office to allow him to play for Manchester United.
Anderson may have to wait before moving to Old Trafford
The initial application for Anderson's work permit was rejected because he had not played in 75% of Brazil's internationals over the last two years.
But United, who agreed a deal with Porto for the 19-year-old midfielder in early June, have now won their appeal.
United told a six-man panel that only Anderson's youth had prevented him from meeting the set criteria.
They also argued he will bring exceptional talent to the Premier League.
Anderson made his debut for Brazil in their 2-0 Copa America defeat to Mexico on Wednesday.
Anderson said earlier this week: "To join Manchester United at 19 is incredible.
"Everything will be different in England - I know that - but I am certain I will adjust quickly to life in England.
"I am proud - and my family is also. For me, everything is new, it's a dream come true."
His move to United was announced at the same time as Sporting Lisbon youngster Nani, who as a Portuguese citizen has no work permit problems.