Manager Louis van Gaal was unhappy with his team's performance at the King Power Stadium on Sunday, where they conceded four goals in the last 28 minutes, and told his squad to meet for a detailed debrief 24 hours later.
Van Persie said "confronting" views were exchanged during the meeting, which he feels was beneficial to the squad as they look to improve following their worst start to a Premier League campaign.
Nearly a week on from the capitulation, Van Persie is still at a loss to explain how United failed to win the match, which they led 3-1 thanks to his first goal of the season, and strikes from Angel di Maria and Ander Herrera.
"It shouldn't be possible, but it still happened," Van Persie told Fox Sports ahead of Saturday's home game against West Ham.
"So we have to deal with it
We had a proper look at it the next day.
"Sometimes it was a bit confronting.
"It was a really good meeting as everyone spoke up and shared their feelings.
"It was a long meeting, one hour or something meeting, but we went from there, started again this week and a couple of really good sessions in and everyone feels ready to face West Ham."
Spirits were high before the start of the season following United's successful tour of the United States, but Van Gaal has endured a poor start to life in England.
The former Ajax and Bayern Munich manager has recorded just one win so far, against relegation candidates QPR.
Defeat to West Ham would raise further questions about Van Gaal's ability to take United back into the Champions League, but Van Persie is sure his fellow Dutchman is the right man to revive the club's fortunes following the failures of David Moyes' reign.
"I think his numbers speak for themselves, he has had success everywhere he has managed," said Van Persie, who captained Holland under Van Gaal at the World Cup.
"And everyone believes in his philosophy as well.
"If you look at the players we have now, the staff, the stadium, and the fans, I am very confident for the future."
Much to Van Gaal's dismay, he has been hit by an injury crisis ahead of the visit of Sam Allardyce's side.
Summer signing Marcos Rojo is United's only fit centre-back as Jonny Evans, Phil Jones and Chris Smalling are injured while Tyler Blackett is missing through suspension.
Teenage defender Paddy McNair could make his first-team debut on Saturday and l eft-back Luke Shaw is expected to make his debut, following his arrival from Southampton this summer
West Ham manager Sam Allardyce has warned Ravel Morrison his loan spell at Cardiff is his last chance to prove he is worthy of a future at Upton Park
The 21-year-old has moved to south Wales for three months having played just 33 minutes in the Premier League so far this season.
Morrison, who is currently on bail until the new year on assault charges, tweeted ahead of the move that his talent was going unnoticed in east London.
"I got no ratings off people in the club not the club itself just people in it," he wrote before later adding: "I've got 0% ratings at West Ham."
After moving from Manchester United, where he was originally considered a marvellous prospect, Morrison has spent time at Birmingham and QPR whilst being used sparingly when available to Allardyce.
And now the England Under-21 midfielder appears to be in the last-chance saloon with his manager.
"He can go and play some football and see if he can get regular first team football and we can keep him an eye on him," Allardyce said in explaining the loan to the Sky Bet Championship side.
"And then in and around Christmas time we have to make a decision regarding Rav because he's coming into the last year of his contract now.
"It's not that he has to impress me as a footballer, we know about his talent
It's about playing the talent and himself to a disciplined life in general, is what needs to happen with Rav
If that happens we'd want him here."
West Ham will be without midfielder Cheikhou Kouyate
The Senegal international has been ruled out with a groin injury suffered in the 3-1 win over Liverpool and could be missing for up to six weeks
Captain Kevin Nolan is back in training following a fractured shoulder but will not be considered at Old Trafford, whilst Matt Jarvis (thigh) is in a similar position
Joey O'Brien (knee) and Andy Carroll (ankle) are also missing but James Collins is in contention to start after coming off the bench last weekend
Source : PA
Source: PA