A 4-0 defeat at Old Trafford keeps Adams' men precariously perched just a point above the drop zone.
Norwich found themselves inside the relegation places at one stage on Saturday afternoon, but Hull City's battling 2-2 draw at Fulham means they have kept their head above water.
Consolidating in such a position will be no easy task, with fixtures against Chelsea and Arsenal to come, and Adams concedes that better match-management will be required if they are to preserve their Premier League status.
He told Sky Sports on a game which turned shortly before the interval when Danny Welbeck was bundled over inside the box by Steven Whittaker: "I think we did really well in the first half with the shape - frustrated them, kept it quiet, and then five minutes before the end they get the penalty. I've just had a quick look at it, there is minimal contact. I think he probably hit him with the arm rather than the feet.
"Obviously that then changes the game. You go in at half-time 0-0, you feel you can build on it, but second-half wasn't good enough.
"To allow (Wayne) Rooney to shoot from that sort of distance, get shots away, you're going to be punished. We didn't learn our lessons from last week - (Raheem) Sterling did a similar thing - and then effectively the game is over.
"We had a go, we tried, but when you're 2-0 down away from home at a place like this it's always going to be difficult. I just felt we needed to be better second half."
Asked if it will be possible for Norwich to pick themselves up following another demoralising setback, Adams added: "We're going to have to.
"Overall, today's performance wasn't good enough, it wasn't what we've produced in the other two games. But we're still above the line, there is still two games to go and what we can't do now is beat ourselves up and think we're in big trouble.
"Of course we're in the situation, we know that, but the two games we're capable of getting something - albeit it's hard to say that after the second-half performance today.
"The last two games, we've got to believe in ourselves and give everything we've got."