Ole Gunnar Solskjaer’s side needed only a point from their final Group H contest in Germany on Tuesday night to secure progression through to the last 16, though found themselves 2-0 down and with a mountain to climb inside 15 minutes after sloppy defending contributed to goals from Manchester City loanee Angelino and Amadou Haidara.
While United were improved after the interval, substitute Justin Kluivert added a third with 20 minutes to go for Leipzig, who then withstood a late onslaught as Bruno Fernandes netted from the penalty spot after a foul on Mason Greenwood and substitute Paul Pogba headed in to set up a grandstand finish.
Nordi Mukiele came close to notching a stoppage-time own goal that would have sent the Red Devils through in dramatic fashion, though in the end they were made to pay for such a dreadful opening in a costly 3-2 loss at the Red Bull Arena.
“We started the game too slow,” Maguire told BT Sport. “Wasn’t good enough the first 20 minutes, we weren’t at it and they scored their two chances. They put two balls in the box and we failed to deal with the cross and that’s why we’ve been beaten.
“Second half we gave everything, and they’ve scored with their only attack. Another cross, so we’ve got to look at ourselves really. We gave ourselves too much to do. We’ve been coming from behind so had great belief we could do it, you see how close we came at the end.
“The amount of chances we’ve had, the shots we’ve had, I don’t know the stats. Ultimately we started the game too slow, giving goals away and falling behind.”
United switched to a different system in Leipzig and then changed shape again more than once during an eventful contest, though Maguire was not interested in leaning on that as a reason for their shortcomings.
“This club deserves to be in the competition,” he said. “We have to get through the group. We knew, no matter what group it was, it was going to be tough but we have to do more.
“We looked at the group and felt we should get through, those are the standards of the club. I’m the captain, I’m disappointed, I’m gutted for everyone because we worked so hard to reach this competition.
“I don’t want to look at excuses. There are 11 bodies who have to go out there and be aggressive, win the first balls, win the second balls and defend crosses.
“It’s the basics of football. It doesn’t matter what shape you are in, if you can’t defend crosses you are going to lose football matches.”