Rio Ferdinand has insisted that Manchester United players have 'downed tools' in recent games.
United fell to a disappointing defeat at the hands of top four rivals Newcastle on Sunday as the Magpies leapfrogged the side into third in the Premier League table.
The result means the Red Devils are winless in three Premier League games after losing 7-0 to Liverpool and drawing 0-0 with bottom side Southampton before the international break.
They face a fight to finish in the top four at the end of the season, with the side currently fifth and behind Tottenham following Spurs' draw with Everton on Monday.
Ferdinand slammed the players' attitude on his FIVE show, insisting they have let standards slip since winning the Carabao Cup in February.
'It seems like they've won the Carabao Cup and downed tools,' the former United defender began. They think they've done enough, that's what it feels like. They've got to get out of this rut.
'The performance on Sunday. Seize the moment! It's the moment, it's top four. Take the opportunity. Understand what is there. What are the requirements for you?'
Ferdinand called for United's players to be more aggressive in dealing with their recent issues.
They have already picked up one trophy this season, but are still fighting for two more, with the possibility of winning the FA Cup and Europa League still present.
The 44-year-old called for the players to 'strangle' each other to understand the seriousness of the situation.
'Luke Shaw mentioned they had a meeting after the game,' he added. 'They need to be strangling each other, there needs to be some pushjing and shoving, up in people's faces. So people understand this is the serious business end of the season.
'If David de Gea doesn't play we're bang in trouble, it's probably five or six.
'I thought mentally they'd got beyond this. I thought we'd eradicated the feeling of the Brentford game (earlier in the season). I hope it won't rear it's head again.'
United are back in action on Wednesday when they face Brentford at Old Trafford in league action.