Damaris Egurrola, who was born in the United States to a Dutch mother and Spanish father, played for Spain at the youth and senior level for four years before switching allegiances to the Netherlands in 2022.
Aniek Nouwen and Lieke Martens each played professionally for five years in Spain, while Stefanie van der Gragt played there for two.
"So, of course we spoke with our players knowing a lot about Spain. Of course our scouting team did its job. Of course my staff did the job, and I did myself the job. So we know everything about Spain," Jonker said. "We have a small book about them. I think they won't surprise us.
"We hope it will be helpful, but then in the end, you don't win a game in the preparation. You have to win it on the pitch."
Ninth-ranked Oranje were runners-up to the United States at the global showpiece four years ago in France. This time around, they drew 1-1 with the US to go undefeated through the group stage.
They then beat South Africa 2-0 in the round of 16, while sixth-ranked Spain crushed Switzerland 5-1 in their last-16 match.
Jonker said while his squad might have been a step behind Spain a year ago, they are not any longer.
"The question is have we closed the gap? We played two top games against Germany (a 1-0 loss in their most recent defeat, on April 7) and against USA, and in those games we've shown ourselves we have closed the gap," Jonker told reporters.
"We want confirmation, so (Saturday) is another top game, and we think we can beat the Spanish."
The Dutch have faced an exhausting World Cup travel schedule with group games in Dunedin and Wellington, in New Zealand, before heading to Australia for their first knockout game in Sydney, then back to Wellington for the quarter-final.
"There was no option to change anything," said Jonker.
"We said 'Listen, it's so many airports, it's so many hotels, it's so many pitches, so many flights.' We have accepted it. I think we are world champions of flying already now."
The match will be shown live at 3am in Spain and the Netherlands, a time slot intended for the US, who instead crashed out in the last-16.
Jonker encouraged Dutch fans to rise early to watch.
"If you like good football, if you like the fight, if you like tension, then watch it," the coach said. "I can imagine it's difficult to get up in the middle of the night, but if you really like it then get up."
