Manchester United manager Ole Gunnar Solskjaer said Sheffield United "wanted it more than us" during Sunday's pulsating 3-3 Premier League draw at Bramall Lane.
The Red Devils were largely awful against Chris Wilder's side and found themselves 2-0 down after 52 minutes courtesy of goals from John Fleck and Lys Mousset.
Three goals in seven minutes from Brandon Williams, Mason Greenwood and Marcus Rashford looked like securing an undeserved victory for Manchester United, but Oli McBurnie struck in the final minute to ensure a share of the spoils.
"It's not something you can put your finger on here and now, but they looked like they wanted it more than us," Solskjaer told Sky Sports. "They believed in what they did more than us, but sometimes it's little margins here and there.
"We maybe had one shot on target in the first half and that's not acceptable; not good enough.
"It's football. Sometimes it's beyond the tactics; it's beyond the passion and drive. The supporters in the first half and the energy of their team compared to ours was such a big difference. Then we get the goal and our energy comes back and the belief comes back in."
Despite failing to hold onto their lead and claim all three points, Solskjaer believes his side's comeback from two goals down shows they have improved since last season.
"The difference between this team and last year's team is huge," he said. "At 2-0 down, my mind is going back to Everton [they lost 4-0 in April]. Last year we'd have been beaten three, four or five. This is such a big stride forward for them, coming back from 2-0 down to 3-2 up and then of course towards the end, things like that happen.
"It's mixed emotions. You can't be happy because we've not performed for the majority of the game, but then the attitude and the way they turned things around shows what we're capable of."