West Ham United boss Sam Allardyce believes Louis van Gaal must start winning with Manchester United.
Allardyce wrote in the London Evening Standard: "Only time will tell if he has a United team who will challenge at the top end of the table and it's an absolute certainty that, after spending £131million, they have to be back in the Champions League next season.
"When you spend that kind of money, there is bound to be pressure for instant success, no matter who the manager is and what his pedigree is.
"Van Gaal has been at some of the world's top clubs so he will know and understand all about that level of pressure. He has handled it many times.
"He has been quoted as saying it may take him a year to get things right but you just don't get that sort of time these days.
"We managers only buy time by making it ourselves and the only way we do that is by winning matches.
"If United have to win ugly for a while, then that is what they will have to do because the United fans are no different to any others in that they will not countenance consistent defeats, whether you need a year or not.
"You will continue in your position only if you get results."
