The 18-year-old winger was one of the stars of Spain's European Championship triumph two years ago, but he has yet to hit top form in the United States. While players such as Lionel Messi, Kylian Mbappe and Erling Haaland have grabbed the headlines with goals, Yamal has managed just one goal and is still waiting for his first assist of the tournament.
De la Fuente believes there is much more to come from the teenager, who arrived at the World Cup after recovering from a late-season injury.
"We know that the best version of him, the attacking Lamine, is something that we haven't quite seen yet in this World Cup. Not to the level that we're used to," said De la Fuente.
Although his numbers have been modest, Yamal has remained a constant threat on Spain's right wing and has regularly stretched opposition defences with his pace and dribbling.
The Spain coach was full of praise for Yamal after the 1-0 last-16 victory over Portugal, describing it as one of the youngster's strongest displays. Speaking ahead of the Belgium clash, he explained why he rated the performance so highly.
"We were facing a powerhouse of a rival, and the defender who was marking him ultimately had to do so much that he was injured," said De la Fuente, referring to Portugal full-back Nuno Mendes, who was forced off during the second half.
De la Fuente also believes the challenges of playing at a World Cup have helped Yamal develop despite his young age.
"He doesn't need extra motivation. You actually sometimes have to calm his intensity. He's very motivated - he wants to do so much," the Spain boss said.
Spain head into the quarter-finals with an impressive defensive record, having yet to concede a goal in the tournament. However, they face a Belgium side full of confidence after scoring four goals against the United States in the previous round.
De la Fuente is confident Yamal can make the difference when Spain need him most.
"He's going to perform on the attacking front - that's very clear," he said.
"He's got incredible potential. And, of course, this is yet to come in some respects."
France will face the winner of the Spain vs Belgium quarter-final match in the World Cup semifinals on 14 July at Dallas Stadium.
