Lisandro Martinez launched a scathing attack on the Manchester United board after Tuesday’s 2-0 loss at Atletico Madrid.
The Red Devils produced a much-improved performance at the Metropolitano Stadium following the disappointing home draw against Tottenham Hotspur.
But individual errors meant they had to return empty handed from the away Champions League fixture.
The result has piled pressure on head coach Michael Carrick whose team is now on a five-game winless run.
Talking to the media after the match, Martinez called out the club’s technical director Jason Wilcox for not supporting Carrick in the transfer market.
He said: “I expect more [investment]. 100%. I expect more from our technical director [Jason Wilcox].
“I have to be honest, as players we have to do more but it is also important when you make a strong squad to be ready for this kind of night.”
United endured a disappointing summer transfer window.
The club failed to bring in striking support for Benjamin Sesko and competition at left-back for Luke Shaw.
They spent around £155 million to sign Youri Tielemans, Andrey Santos and Carlos Baleba.
Elliot Anderson, Mateus Fernandes and Aurelien Tchouameni were their primary midfield targets but missed out on all of them.
United refused to pay an exorbitant fee for these stars, with the club’s transfer policy changed under INEOS.
But their cautious approach in the market means the club’s performances on the pitch this season have been massively underwhelming.
Man United are currently 13th in the Premier League, having won just one of their six matches.