A troublesome start to David Moyes' tenure took a sharp downturn on Saturday as West Brom recorded their first win at Old Trafford since 1978.
It was United's third loss in six Premier League games, representing their worst start to a league campaign since 1989.
They have not scored a league goal in open play since their trip to Swansea on the first day of the campaign, have now fallen eight points behind early pace-setters Arsenal and hover just three above the relegation zone.
Bookmakers have delivered their own verdict, shoving United out to 7-1 fourth favourites to retain their title and, on the odds alone, in a battle with Tottenham even to qualify for next season's Champions League.
It is a scarcely believable situation given United won the championship by an incredible 11 points last term, Sir Alex Ferguson's final one in charge, and led to doubts being expressed by some fans over David Moyes' suitability as replacement.
Yet Buttner is adamant there is no need to panic.
"I don't think it is a crisis," said the Dutch defender.
"Of course the crowd want to see Manchester United winning - the players want that too.
"We have lost games and if we lose we are not happy."
Various factors have already been highlighted for the Red Devils' present slump.
The sheer upheaval created by Ferguson's exit is an obvious one, while Moyes' comment that United "didn't defend well at all but didn't attack well at times either" told its own story on a sobering day, with Moyes also casting doubt on the club's Champions League credentials in quotes carried by some of the Sunday newspapers.
Yet, with the exception of Paul Scholes' retirement, the arrival of Marouane Fellaini and Adnan Januzaj's elevation to first-team duties, it is exactly the same squad that romped to glory in Ferguson's final campaign.
"You always have to trust the players," said Buttner.
"I think we can do this as a team. Our season starts here. We are going to win games, I am sure about that."
Throughout the transition process, United have depicted themselves as having a long-term vision.
As Ferguson personally rubber-stamped Moyes' appointment, there is no chance of the Scot coming under any internal pressure even if externally the scrutiny following such a woeful start is likely to be intense.
Even the prospect of finishing outside the top four will not have United's hierarchy trembling as they believe the club's finances are robust enough to ride the loss of Champions League income as the club plots a path through such uncharted waters.
Moyes would have been gratified to hear there were as many supportive calls to radio phone-ins on Saturday night as there were negative, with most fans adopting a realistic view of United's plight given the widespread acceptance that two titles and two runners-up finishes represents a massive overachievement since Cristiano Ronaldo's exit in 2009.
There are legitimate questions being asked of Moyes though.
The Scot's continued refusal to select Shinji Kagawa in a central role - he suffered the ignominy of being replaced at half-time against West Brom - do not suggest he is convinced by the Japan star.
Even more baffling, the decision to overlook £15million forward Wilfried Zaha completely came after the former Crystal Palace man was one of the success stories of United's pre-season tour.
The botched transfer window has left United obviously short of dynamism in midfield.
With no chance to address the situation until January, it is hard to envisage Moyes forcing his team back among the title challengers and, for the second week running, they head into a tricky cup tie - Wednesday's Champions League trip to
Shakhtar Donetsk - needing to stabilise the situation.
"In football you're not going to win every game," said Moyes.
"That is part of the job. You have to support your team.
"The good thing is there are lots of games here and we will be ready for the next one.
"This is a great club with great players and we'll do everything we can to put this result behind us."