Michael Carrick said the boos at Old Trafford "hurt" after the 1-1 draw with Tottenham condemned Manchester United to their worst start to a season for 40 years.
United's points tally of six is their lowest total after six games since 1986.
- '51 years': Utd fans mock City with trophy banner
- Carrick: No timeline for Sesko's Man United return
There were boos during the game and after the final whistle against Spurs and Carrick said afterwards the reaction of the home fans was difficult to take.
"Obviously, it hurts, you know, it hurts a lot," said Carrick in his post-match news conference.
"It's not nice to go through, but sometimes you have to go through it. That's how it is, you know. It's coming from a good place, really, and so I understand it."
United looked on course for their second Premier League win of the season when Bryan Mbeumo's opener was quickly followed by a Tottenham red card.
Rodrigo Bentancur, on as a substitute, was dismissed for aiming a headbutt at Luke Shaw. But rather than use the advantage to help get over the line, United contrived to gift Dominic Solanke a 92nd-minute equalizer.
It's the second time this season that Carrick's team have dropped points after conceding in stoppage time and also the second time they've failed to beat a team with 10 men after losing to Manchester City last month.
"It's a couple of times now when -- different ways obviously -- that's two late, late goals against us to throw away two wins really," Carrick said.
"We need to do better with seeing out games, that's for sure, once we get ourselves in a good position.
"It's definitely something where -- 10 men or not 10 men -- if we're ahead in the game we've got to see games out. Certainly, we need to improve that."