Goalkeeper Yann Sommer was pressed and put a completely misdirected pass straight to Mikel Merino who poked the ball to his name Mikel Oyarzabal who in turn scored.
Oyarzabal, who is a teammate with Alexander Isak in Real Sociedad, also had a great opportunity to make it 2-0 on posts at the beginning of the second half but then he did not succeed.
The match ended 1-0 and Spain is still undefeated after three matches in this year's Nations League.
Switzerland, on the other hand, has not yet won.
Mistake also in Kiev
In the second match in Group 4 of the a-division of the Nations League, Ukraine hosted Germany in Kiev.
1-0 came after 20 minutes through Matthias Ginter.
Georgi Bushchan in Ukraine's goal made some great saves, but in the 2-0 goal he also made a mistake.
All he needed to do was pick up a good pass, but messed it up and give Leon Goretzka the chance to nod.
That score was decisive when Ukraine got a penalty and Ruslan Malinovsky put the reduction to 2-1 with just under a quarter left to play.
CLIP: Alexander Isak broke the goal drought against Russia (8/10)
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Alexander Isak broke the target drought against Russia Photo: Bildbyrån.