The Swiss, who play the Republic on September 8 in Basel and travel to Lansdowne in the October 12 2005 return, begin their Portugal campaign against Croatia next Sunday. Two of the toughest matches follow from there with both England and holders France awaiting Jakob Kuhn's side.
Switzerland had numerous chances to make the game safe before Gygax struck but Liechtenstein goalkeeper Peter Jehle had denied strikers Alexander Frei and Stéphane Chapuisat with excellent saves in the first half.
Kuhn also introduced a number of substitutes in the second half that disrupted his side's increasingly desperate attempts to break through Liechtenstein's efficient defence.
There was bad news for Brian Kerr's side with the news that Swiss captain Murat Yakin played a full 90 minutes after limping out (thigh) of their defeat by Germany last Wednesday. 18-year-old striker Johan Vonlanthen also made his debut.