Gary Neville has admitted he's concerned about Manchester United's lack of transfer activity after Chelsea's summer recruitment.
The Blues have been busy this summer after a transfer ban prevented Frank Lampard from making any signings in his debut season at the club.
Having acquired the signature of Hakim Ziyech and Timo Werner, Thiago Silva, Malang Sarr and Ben Chilwell have also arrived at Stamford Bridge.
Bayer Leverkusen star Kai Havertz is next on the list, with the German attacking midfielder close to completing a big-money move to the Premier League.
United, by contrast, are yet to open their cheque book after spending their time haggling with Borussia Dortmund for Jadon Sancho.
Donny van de Beek looks set to be announced as their first recruit in a £40million deal for Ajax but it's been a frustrating summer for United supporters.
With Manchester City actively pursuing a deal for Lionel Messi too, Neville had admitted he's been left concerned by United's rivals' recruitment.
"I think there are definitely four or five players required and to not get three,” he added. “I think it would be a problem because of what the other clubs are doing.
"If Liverpool get Thiago, if Manchester City do what they are looking like they are going to do and with Chelsea doing what they've done, they are your competitors and they all look like they are improving and moving forward.
"So, United have to do business but I do believe more in the strategy of what's happening, they just have to get the deals over the line.
"That's not always easy but they have to try and do it quickly to give Ole the time to build to get this team moulded for the start of the season."
On United's summer business, he added: "It's frustrating at the moment, as a United fan, that the club haven't done their business earlier.
"But there have been times where the club have panicked in the transfer market in the last 10 years, where they've been reactive, where they've overpaid and where they've got it wrong.
"So, you have to be sensible. If the deals aren't there to do, you don't do them, but there's definitely that tension building, particularly on social media.
"Why has Jadon Sancho not signed? Why have we not got Thiago Alcantara?
"Why haven't we got whoever it might be that's gone to another club?"
