Rock_cake
Soccer is a game where sometimes teams that are much better on paper may end up tying or even losing. Scoring is usually relatively low, so a single mistake can be all that needed to change the outcome.
Here is one explanation on how they did it: https://www.nytimes.com/athletic/7364332/2026/06/15/cape-verde-spain-draw-analysis/
There were lots of goalkeeping heroics since Vozinha made eight crucial saves to deny Spain’s star-studded frontline, including a point-blank stop against Aymeric Laporte and tipping a Ferran Torres strike over the crossbar.
They did a very disciplined blocking – defending as a cohesive unit, Cape Verde limited the spaces between their lines and forced Spain to play horizontally rather than breaking through the middle.
They also did lots clearing, and just enough occasional attacks to prevent Spain from throwing everyone forward.
In many sports (i.e. basketball or handball) a significantly better team essentially always wins, but in soccer there is a good amount of luck involved, the fact that defending is easier than attacking, match-ups between individuals and teams, the importance of possible mistakes, and the naturally high variability.