Norway beat neighbors Sweden thanks to Erling Haaland's brace and an assist; Spain beat the Czech Republic; and Portugal were upset by Switzerland, with Cristiano Ronaldo missing.
On Sunday evening, Switzerland handed Portugal their first taste of defeat in the UEFA Nations League, putting Spain atop Group A2.
With Portugal missing talisman Cristiano Ronaldo, Benfica striker Haris Seferovic's first-minute header was enough to give the Swiss a stunning 1-0 victory for their first points of the season. The Swiss had gone winless in their last three outings in the competition, and went to the tie as sport betting underdogs following their recent unwanted form.
The result meant Spain took a one-point lead at the top of the table as Carlos Soler of Valencia and Pablo Sarabia of Paris Saint-Germain scored in an easy 2-0 win over the Czech Republic in Malaga.
Since qualifying for the World Cup in November last year at the expense of group rival Italy, the Swiss had gone on a downward trajectory with a five-match winless streak.
Portugal barely had time to miss Ronaldo or even touch the ball when they fell behind in under a minute. Xherdan Shaqiri's short series of passes set up right back Silvan Widmer for a dangerous cross to Haris Seferovi who scored after 57 seconds.
Despite late pressure from Portugal, including two scoring chances for 39-year-old captain Pepe, the one goal was all they needed to secure three points in Geneva.
Portugal had gone undefeated in five games this year, beginning with two victories in the World Cup qualifying playoffs in March and ending with a 4-0 thrashing of Switzerland last weekend.
Elsewhere in Group B, Erling Haaland continued his impressive goal-scoring record at the international level with two goals, one from the penalty spot, in a 3-2 win against Sweden. Matches were available for betting on the Betway platform for fans across different parts of the globe.
The 21-year-old, who also assisted Alexander Sorloth's crucial third 13 minutes from time, now has 20 goals in 21 appearances for his country and is only 14 goals away from beating Jorgen Juve's record set between 1928 and 1937.
The striker, who just joined Manchester City from Borussia Dortmund, also scored twice in a 2-1 win for Norway against Sweden in the first leg of their League B double-header earlier this month.
Haaland scored his first goal in the 10th minute, darting in front of a defender, and then converted a penalty early in the second half to make it 2-0.
Emil Forsberg scored from a curler to reduce Sweden's deficit, only for Haaland to cross for Alexander Srloth, who in turn headed to the far post.
Viktor Gyökeres scored Sweden's second goal in the fifth and final minute of stoppage time.
Norway leads Group 4 with ten points, three ahead of Serbia, who blew a two-goal first-half advantage to draw 2-2 in Slovenia.
A Bulgarian team drew 0-0 in Tbilisi after their bus was involved in a traffic accident shortly after landing in Georgia.
Georgia is three points ahead of North Macedonia in Group 4, who defeated last-placed Gibraltar 4-0.
Greece topped Group 2 after a 2-0 victory over Kosovo, giving coach Gus Poyet's side a six-point lead in the rankings.
The Nations League resumes today, with more matches lined up across Europe and fans will be able to place their wagers on the Betway website or mobile app.