"I feel very proud of course and especially proud of the players. I don't know if it is the best victory ever, for me the best victory is always the next one. But I don't think I will ever forget this win," he told a news conference.
"We were very courageous in the way that we played and you could say that we are the rebels of this tournament," he added.
Chile controlled their lead impressively having looked sharper and more committed than Spain throughout the first half.
"I think this team is a very mature team and they are probably more mature than ever," said Sampaoli.
"We were already very good in qualifying but we were even better today. Today we played with a system and an idea. The players believe in one idea and defend it.
"We will see if it is the best Chile team ever, that is something we can only say after the tournament is over," he added.
Chile's final game of Group B is against the Netherlands, who have also already qualified, but the top spot in the group remains up for grabs.
Finishing second could well mean facing Brazil in the next round and Chile's Argentine coach said that meant there was no question of easing off against the Dutch.
"Now the most important thing is being to appreciate the way we played and how we were able to stop a team like Spain.
"Up against the Netherlands we need the same effort and we need to be at the same level again. We want to finish first in the group," he said.
But the Chile coach was not ready to start making grand predictions for his team.
"I'm not thinking about Chile as world champions. There are many good teams here and we will see. I just hope we can play with same willingness and dedication as today," he said.
Sampaoli singled out midfielder Arturo Vidal, who had knee surgery last month, for the way he battled against pain.
"Vidal had some problems with his leg in these last few days. He gave a very intense display which is difficult to do when you have constant pain.
"It was incredible what he could do. He is being treated now, he is under control. He knows after every game he is going to feel a certain pain - but he can manage. He played at an intense pace today and so it is normal he is feeling a little pain."
- Sports & Recreation
- Eduardo Vargas