Morocco coach Walid Regragui said his plan was to let Spain have the ball after his side's dramatic penalty shootout win in their World Cup last-16 match on December 6.
Victory took the African side into the quarter-finals for the first time in their history, trumping their performance in 1986, when they reached the last 16.
Morocco won 3-0 on penalties following a 0-0 draw after extra-time at Education City Stadium in Qatar.
Spain dominated possession during the match but Morocco's staunch defence largely kept them at bay and limited clear-cut chances.
"We had agreed not to take possession -- not out of fear," Regragui said. "We are humble enough to say that we are not yet France, Germany or England, to compete with them in terms of possession.
"Nobody managed to steal the ball from them, so I accepted not having the ball. I'm not a magician."
Regragui said the team worked for four days on their gameplan to reduce the impact of midfield trio Sergio Busquets, Pedri and Gavi.
"Having closed so many passing lines for 120 minutes, we knew we would have chances -- we had two, three, four," he said.
"We did not know how to punish them. The gameplan was respected, we got to penalties, and then it's a lottery.
"But when you have such a [great] goalkeeper in goal, you know you have a better chance of succeeding."
Morocco goalkeeper Yassine Bounou denied Carlos Soler and Sergio Busquets from the penalty spot, while Pablo Sarabia hit the post as Spain failed to score any of their three penalties.
Achraf Hakimi, born in Madrid, dinked in the Panenka penalty that won the shootout for Morocco, continuing their fairytale run in Qatar.
The North African side topped their group, beating Belgium and Canada, while drawing with Croatia.
They have only conceded one goal in their four matches.
"Since the start of the competition, we've been playing with a team that's not 100 percent, that's why it's even more extraordinary," said Regragui.
"We've managed to create a family, and we feel that we have a people behind us.
"If you had told me before starting that we would face Croatia, Belgium and Spain without losing a match, I would have signed for it."
Regragui hailed his squad.
"Big congratulations to the players, they did something extraordinary, in the frenzy of energy, in the desire not to let go of this match," he said.