Manchester - Manchester United manager Louis van Gaal says British record signing Angel Di Maria should be given more time to justify his price tag and be judged on his success at Old Trafford.
Di Maria joined United for £59.7m from Real Madrid last summer as part of United's re-building plans under van Gaal.
But after an encouraging start to his career in British football, the Argentina international, 27, has struggled to find his best form in a United side, which despite occupying a top-four place in the Premier League has also stuttered at times.
Di Maria was substituted at half-time during United's unconvincing 2-0 win over Sunderland last Saturday and looked a frustrated figure.
His home near Manchester was the subject of an attempted burglary in January which also unsettled the player and his family.
Van Gaal admits that all players need time to find their feet and says it's too early to judge Di Maria's impact.
The United manager said: "I think it counts for all the players that we have bought, the first season is always difficult. I have explained that in the press conference after the match (against Sunderland).
"You can see it for every player we have bought, Shaw, Blind, Herrera, Falcao and also Di Maria.
"For me it is not a big surprise, it is more a big surprise when he adapted as quickly as possible.
"In Holland, Spain and Germany I had the same experience with players. We have to give him time, not just Di Maria but all the players. We wait and see."
Van Gaal hopes that next season will see all his recent signings fulfil their potential, although he admits there is no set formula for how long it takes a player to fully settle at a new club.
He added: "It is dependable, you have to manage so many aspects. Not just the game, but the culture.
"The general answer is one year but you can't give a general answer. It is easy to say that, I cannot prove that. It is not scientifically proven."
United's re-built squad has looked unconvincing at times but has been beaten only twice in the league since the beginning of November.
Some home supporters appear to be losing patience at United's methodical style but van Gaal insists he was happy with the overall performance in beating Sunderland with a game to come against further North East opposition - at Newcastle United - on Wednesday night
He said: "I remember the fantastic goal that Rooney scored after a fantastic counter. I have seen the match again and I think we played a good match.
"We won very deservedly, could have won more but it is always like that."
Striker Robin van Persie is again missing for United's trip to St James' Park with an ankle injury with van Gaal saying it is still too early to say how long the Dutch international will be out.
United have no other injury worries and midfielder Michael Carrick could play a part against his hometown club after being an unused substitute against Sunderland.