Levein's men needed a dramatic 97th-minute header from defender Stephen McManus to beat the Group I minnows 2-1 in the nervy qualifier at the national stadium in September last year.

Scotland go into the return game in Liechtenstein in a precarious position, two points behind second-placed Czech Republic with both countries having two games remaining.

Levein's men conclude their fixtures against runaway group winners Spain in Alicante on Tuesday night, while the Czechs play Spain in Prague on Friday night before finishing their campaign in Lithuania.

The Scots, therefore, need a win on Saturday to have a realistic chance of making the play-offs and many pundits and Tartan Army members are taking that outcome for granted.

However, Levein insists that will require improvement from the last encounter between the two countries when McManus's last-gasp header spared a nation's blushes.

He told Press Association Sport: "We don't really need any evidence to show that if we are not at our best then we won't be successful because the last time we played them we weren't at our best and we struggled to beat to beat them at home.

"And if we put in a performance like that this time, we won't beat them.

"I am not worried about the pundits and fans, how they view Liechtenstein doesn't have an effect on how we play.

"What I'm really concerned about is that we make sure that the players and I understand the nature of what we are facing."

The former Scotland defender continued: "I get the chance to see Liechtenstein regularly.

"They have taken four points off Lithuania, the same as we have, and were very unlucky recently against Switzerland.

"There is an understanding in their team which makes it very difficult to break them down.

"The good things for me is that we have a good group of players who don't take their foot off the gas.

"I can say that there hasn't been a game when I felt that we weren't 100% on it, and that's what we need to be, focused, and play the game with an intensity.

"If we don't move the ball quickly then we will struggle."

The Scotland squad flew out from Glasgow Airport this morning for their Switzerland base without skipper Darren Fletcher who is ruled out of the first match after being struck down with tonsillitis, although it is hoped that the Manchester United midfielder will have recovered for the game against Spain.

Striker Kenny Miller has a minor tear in his groin and is also likely to miss the Liechtenstein game but he travelled and is hopeful of being fit to face the Spanish.

Levein knows there is little else he can do but wait to see what the next few days bring but is unwilling to offer "false hope" of Fletcher being available for the Spain game and insists he will not gamble with Miller.

"I thank Darren for every match because he is our captain and arguably our best player," said Levein

"So I would like to have him available.

"Every time he is not available, it is a blow for us.

"He is improving, I spoke to him last night and he is feeling better so I'm hopeful but I would not want to give anyone false hope.

"Kenny Miller is also improving. He will train on Friday but I won't take a chance."

Aston Villa defender Alan Hutton has recovered from a knee knock while Graham Dorrans and Barry Robson have shrugged off their respective ankle and thigh complaints.

Peter Houston admits he will tune in to the Czech Republic versus Spain game on Friday night with some trepidation.

"I will probably be nervous," said the Scotland assistant.

"It's natural. We want the Spanish to do well and then have an off day against us on Tuesday.

"That's what we can only hope for."