The United boss took a swipe at the club’s own supporters earlier this week for those who he claimed weren’t showing enough support for Romelu Lukaku.
And Mourinho has recently aimed a sly dig at Chelsea boss Antonio Conte, stating he “never speaks about injuries” while other managers “cry, cry and cry”.
When Conte was was asked about Mourinho’s comments in his following press conference, he told the Portuguese coach to mind his own business.
Mourinho has often enjoyed playing mind games against his rival managers and has had numerous clashes with the likes of Pep Guardiola, Arsene Wenger, Conte and more.
The 54-year-old has also drawn criticism in recent weeks for taking a defensive approach in games against Liverpool and Tottenham.
But United legend Keane has bluntly told Mourinho to block out the negativity instead of reacting to it.
“My only concern about Mourinho is that he seems to be distracted by the so-called critics out there,” Keane said on ITV’s Champions League Show.
“He is probably paid eight, nine or ten million pounds a year so focus on your own job.
“Rise above that. He should be better than that, but he seems to be easily upset.
“Shut up and get on with your job. You are getting very well paid for it.”