Haris Seferovic scored a hat-trick as Switzerland completed a scarcely believable comeback to thrash Belgium and qualify for the last four of the UEFA Nations League.
Thorgan Hazard scored twice for Belgium in the opening 17 minutes, leaving the Swiss needing at least four goals to progress.
Ricardo Rodriguez gave them hope with a penalty before Seferovic scored from close range and then smashed them into the lead.
Nico Elvedi headed in their fourth before Seferovic's third.
Switzerland will now play in next June's Nations League semi-final against hosts Portugal, England or whoever progresses out of France and the Netherlands.
Swiss looked out of it after bad start
Switzerland fans must have been thinking about leaving after Hazard's two early goals in Lucerne.
He took advantage of Elvedi's weak back-pass from brother Eden Hazard's ball to give them a second-minute lead and then smashed another into the bottom corner.
A 1-0 or 2-1 win would have done for Switzerland but because of away goals in their head-to-head record with Belgium, they needed to win by two goals once Belgium had taken a 2-0 lead.
Against the side ranked number one in the world - and after such an electric start for Belgium - that was looking very unlikely.
