Pundit Robbie Savage has said it is essential that Manchester United give manager Louis van Gaal the funds required to strengthen the side, and has said between now and the end of the transfer window could arguably be the biggest in their modern history.
United had a poor season last year where they finished seventh in their first season after the glorious reign of Sir Alex Ferguson, and this campaign started in a similar vein to the last one with a 2-1 defeat to Swansea City at Old Trafford on the opening day of the season last weekend.
In his Daily Mirror column, the former midfielder wrote: "Louis van Gaal needs three world-class signings before the transfer window shuts because the opening-day defeat by Swansea laid bare - in front of a worldwide TV audience - how United are miles away from the level needed to challenge for the title.
"They looked very average on paper and they were very average on the pitch.
"If that is the going rate they will not even finish in the top six again."
Savage also warned that if Manchester United don't get their business right between now and the end of the window, it could lead to a poor season and a decline that was seen by United's fierce rivals Liverpool - who enjoyed plenty of success in the 1970's and 80's, only to decline in the 1990's.
"It is essential that the Glazers loosen the purse strings and chief executive Ed Woodward pushes through deals for Van Gaal’s main targets.
"It is not too late for Van Gaal to add world-class talent to his squad. Big names will still come to Old Trafford if United’s exile from Champions League football is only for one season.
"So these next 10 days are arguably the biggest in United’s modern history. Sign three or four BIG names, and LVG will be in business - but if they miss the boat, United will be in massive trouble."
So far Manchester United have signed Ander Herrera, Luke Shaw and Marcos Rojo and have been linked with Real Madrid star Angel Di Maria along with Juventus midfielder Arturo Vidal.
How big is the remainder of the transfer window for Manchester United?