Erik ten Hag's decision to ditch Cristiano Ronaldo was the beginning of his downfall at Manchester United, according to Wesley Sneijder.
The United manager clashed with the Portuguese star after dropping him to the bench during the early weeks of his Old Trafford tenure.
Things reached a head when Ronaldo told Piers Morgan he felt 'betrayed' by Ten Hag and wanted to leave the club, making several scathing comments about the set-up.
Ronaldo's contract was terminated by mutual agreement with immediate effect and he went on to sign for Al-Nassr in Saudi Arabia.
While United looked stronger in Ronaldo's absence last season, they have struggled this term and look likely to miss out on Champions League qualification.
Erik ten Hag and Cristiano Ronaldo clashed at the start of last season, leading to the Portuguese star's departure from Manchester United
Now, Ten Hag finds his position under threat following a difficult second season at United
Former Netherlands midfielder turned pundit Wesley Sneijder blamed Ten Hag's demise on his fall-out with Ronaldo last season
Former Netherlands midfielder Sneijder gave a forthright opinion on the causes of Ten Hag's problems as he fights to keep his job.
'Should I tell you where it went wrong for Erik ten Hag?' He told Veronica Offside, as per Voetbal Primeur.
'On the day that he decided to battle Cristiano Ronaldo. That's where he started losing all the respect.
'He thought it would work out well for him, but it's the opposite.
'Everyone in the dressing room wondered if he is alright in the head by doing that.'
Ronaldo was comfortable United's top goalscorer in 2021-22 with 24 but didn't suit the way Ten Hag wanted to play.
The Dutch coach is under serious pressure and could lose his job even if United beat Manchester City to win next month's FA Cup final.
New part-owner Sir Jim Ratcliffe and his Ineos team are weighing up whether Ten Hag is the right man to take United forward.
Mail Sport reported on Monday that Ten Hag's former club Ajax are interested in taking him back.
However, sources insist Ten Hag and his coaching team would be reluctant to walk away from Old Trafford in order to facilitate a return to Amsterdam, meaning Ajax are reliant on him being sacked.
Ten Hag's future appears increasingly tenuous after a frustrating campaign for United
Sneijder described United winger Antony as 'embarrassing' after he goaded Coventry players
After winning on penalties, Antony was seen cupping his ears towards the Coventry players
There is acknowledgment that if Ten Hag loses his job, he may prefer an opportunity at one of Europe's stronger leagues over returning to Holland.
Ajax are currently fifth in the Eredivisie, 35 points adrift of leaders PSV.
Last week, Sneijder slammed United winger Antony as 'embarrassing' after he goaded Coventry City players after his team scraped past the Championship side on penalties in the FA Cup semi-final.
'Antony should be absolutely embarrassed for what he did,' Sneijder told Ziggo Sport.
'He should have walked straight off the pitch instead of doing that. I hope Manchester United lose 5-0 in the final.'