Mourinho wanted to make four signings in the summer and after capturing Victor Lindelof, Nemanja Matic and Romelu Lukaku, he set his sights on bringing a wide player to the club.
Perisic was Mourinho’s preference but Inter Milan were unwilling to do business despite United offering around £40million.
The Croatian remained at the San Siro at the end of the transfer window and then signed a new contract.
Marcus Rashford and Anthony Martial have played wide for much of the season for United but been inconsistent leading Mourinho to rue the failure to sign Perisic.
And according to the Manchester Evening News, sources near to Mourinho think United didn’t offer close enough to Inter’s £50m price tag, and that has led to Mourinho complaining about transfer budgets.
That claim comes as the Portuguese coach voiced his unhappiness about a lack of spending at United.
Since he joined United in 2016, they have spent around £286m on transfers.
But Mourinho claimed it was not enough if they want to compete with Manchester City.
He said: “You think Milan is not as big as us? You think they are not as big as we are? You think Real, Inter Milan is not as big as we are? There are many big clubs.
“I know what is a big club. One thing is a big club and another thing is a big football team. They are different things. We are in the second year of trying to rebuild a football team that is not one of the best teams in the world.
“When you speak about responsibilities to win the Premier League, Tottenham doesn’t have that because they don’t have a history of winning the Premier League? Chelsea doesn’t have it? Arsenal doesn’t have it? Manchester City buy full-backs for the price of strikers.
“It is not enough. The price for the big clubs is different for the other clubs.
“The big historical clubs, they are normally punished in the market for their history. The boys are doing what they can and they are doing fine.”