The Barcelona forward scored twice, while Marc Pubill and Nico Williams were also on target as Luis de la Fuente's side overwhelmed the visitors at the Ramón Sánchez-Pizjuán.
Lamine was asked afterwards about his first goal, which saw him finish at the near post after beating Croatia goalkeeper Dominik Livakovic.
“I already know him from training. I thought about what he does in training and the ball went in,” Lamine explained.
The forward also enjoyed the atmosphere in Seville and said Spain would love to bring the World Cup home to the supporters.
“It gives us great excitement to be able to bring the cup here and show it to the fans, and if we can win it and bring it home, then great.”
Lamine's display inevitably led to more questions about the Ballon d'Or, but he insisted that individual recognition is not what drives him.
“Another one,” he replied when asked whether the performance was another mark in his candidacy.
He then added: “In the end, I don't only play for this Ballon d'Or. I play for myself, for the fans, for the national team and to keep winning.”
Asked whether the performance would influence the voting, Lamine simply said: “I don't vote,” before adding: “We just have to wait and keep playing.”
De la Fuente was equally pleased with the performance and began his post-match media conference by thanking the supporters in Seville.
“Since the welcome, it has been incredible. There has been a sensational atmosphere. We are happy because there has been a great performance. We are an ambitious team that wants to improve. That is the best news,” he said.
The Spain coach highlighted the attacking quality his players had shown against a difficult opponent.
“It is very difficult to do what these players do. The first half could easily have ended 4- or 5-1,” De la Fuente said.
He singled out Lamine for particular praise but stressed that his contribution went beyond the goals.
“He also provided an assist. That makes him an even better player. In the future he will be better because of what he does collectively rather than individually.”
Lamine's two goals, combined with strikes from Pubill and Nico Williams, completed a convincing night for Spain and left the forward describing the occasion in typically simple terms.
“I said before the match that this is when I am happiest,” he said. “A party for me.”