The manager has found himself under even more pressure in the wake of the 2-1 loss in Cardiff, which leaves the Scots second-bottom of Group A.
Asked if the players still back Levein, the Wolves defender said: "It's got nothing to do with the manager - we are the ones who go out on the pitch."
He went on: "We played well, we just maybe ran out of steam a bit. A penalty and a 25-yard strike lost us the game.
"At top-level football, it's the flip of a coin sometimes. We didn't have the luck.
"It's a game we should have won comfortably. Our chances came and maybe we should have killed them off."
Hopes of booking their place in Brazil appear to be all but over for Scotland, who now need victory over favourites Belgium on Tuesday to have any real hope of salvaging their campaign.
Berra knows the odds are stacked firmly against Levein's men ahead of Tuesday's clash in Brussels but he pointed out that Scotland have risen to the occasion in the past when written off.
He said: "We're second-bottom. It's not a great position to be in. But we will look over the game and we will go to Belgium on Monday and prepare for the game on Tuesday.
"They are a top team, with world-class players, but we have done it before. We did in France. When we're down, we always seem to bounce back."