"We know the results haven't been good enough, and neither have the performances over the last week," centre-back Harry Maguire told Sky Sports.
The club's former star player Michael Carrick took over as coach in January after Portuguese coach Rúben Amorim was sacked after 14 months in charge.
“Fantastic football”
Under Carrick, Manchester United took off in the spring. The team finished third in the Premier League and qualified for the Champions League.
"He came in and turned it around for us last season. We played some great football and won a lot of games, but this season we haven't performed well enough as individuals," said Maguire.
Carrick is now under pressure after Manchester United were humiliated away to Como in the Champions League earlier this week. The Italian club won 4-1 after the visitors scored a late consolation goal.
After that loss, team captain Bruno Fernandes was openly critical of Carrick's tactics, and the Portuguese midfielder was on the bench as Bournemouth took on Manchester United on Sunday.
From there, Fernandes watched as his teammates conceded three easy goals. Brazilian Rayan made it 1-0 when he was left unmarked to take a free kick in the 38th minute.
Slipped with the ball
Two minutes before half-time, full-back Leny Yoro slipped while carrying the ball, and Marcus Tavernier made it 2-0.
Just over 70 minutes in, it was 3-0. Manchester United goalkeeper Senne Lammens misjudged a challenge, and Brazilian Evanilson had an open goal.
Manchester United have won just two of their 12 games this season in the Premier League, League Cup and Champions League, and sit 16th in the Premier League with just seven points, just above the relegation zone.
