Haris Seferovic's goal inside the opening minute of play proved the difference as Switzerland held on to claim a 1-0 Nations League victory over Portugal on Sunday.
Murat Yakin's men put in a determined and organised effort to claim all three points on offer in Geneva, while also ending Portugal's unbeaten start.
Switzerland entered the day having lost all three of their Nations League matches, but they needed just 57 seconds to shock the group leaders.
Silvan Widmer picked out Seferovic with an inviting cross from the right, and the Benfica striker made no mistake in angling his header out of the reach of a diving Rui Patricio to score the fastest goal in Nations League history.
Portugal's only real response in the first half came from a Bruno Fernandes corner. The Manchester United midfielder's cross found the head of Danilo, only for Jonas Omlin to acrobatically push the effort away from goal.
Omlin produced another great save, this time from an Andre Silva attempt, after half-time as Portugal continued their search for an equaliser.
Bernardo Silva's introduction brought some much needed energy to the Portuguese attack, but try as they might, Switzerland, and Omlin, continued to turn down their advances.
Nuno Mendes' searching ball picked out Goncalo Guedes, only for Omlin to meet his first-time finish at the near post, keeping his side ahead with under 20 minutes remaining.
The Montpellier goalkeeper, as he did all night, made one last save on a Diogo Jota header, as Switzerland held on for all three points.
The defeat, along with Spain's victory over Czech Republic, sees Portugal fall one point back of La Roja.