The young winger admitted he was a bit surprised Herrera left Bilbao but wished his friend the best of luck.
Athletic Bilbao boss Ernesto Valverde has admitted his disappointment his side could not sign Ander Herrera, but suggests they will not be moving for Arsenal midfielder Mikel Arteta as a replacement.
All the morning news, views and transfer rumours from Old Trafford...
United's new Spanish star has tweeted his appreciation of the welcome he received from his new team's supporters.
Ander Herrera had made it clear he was a Manchester United player before the official confirmation from the club.
Outgoing Manchester United defender Rio Ferdinand believes that Ander Herrera will be a success at Old Trafford if he works hard.
Manchester United's new signing was quick to pay homage to his former side after sealing his move, while touching on his ambitions in England.
The Spanish player has signed a 4-year contract with an option for a further year after completing his switch to Old Trafford.
Ander Herrera has joined Manchester United from Athletic Bilbao.
Athletic Bilbao have announced that they have rejected a bid from Manchester United for Ander Herrera.
Manchester United reportedly in agreement over €36m transfer of Athletic Bilbao midfielder but how does he compare to Barcelona, Arsenal and Chelsea stars?
Manchester United are closing on Ander Herrera, but that's just one part of the deal.
Thibaut Courtois once again succeeds in Spain, while Aymeric Laporte enjoys a breakthrough season.