"This team is at a stage when it can still improve," he told a news conference on Monday two days after they thrashed Belgium 5-0 in a qualifier in La Coruna.
"We are young and we can learn and I am sure we will get better. I hope this team will give more of itself and that our best moment is still to come."
Spain, the world's second-ranked team after Brazil, can seal a place in South Africa by beating Estonia in Merida on Wednesday if Group Five rivals Bosnia fail to beat Turkey.
Vicente del Bosque's side has earned high praise in winning all seven of their qualifying matches but Liverpool striker Torres said the squad were keeping their feet on the ground.
"Compliments can weaken you if that's all you need to be satisfied," he added.
Torres said history would judge whether the current Spain side, with players such as midfielder Xavi and striker David Villa, was the best ever.
"We will see in time," he said. "We have won one European championship, we're putting together some impressive numbers and beating records but we'll have to wait before we know."
The Spanish federation (RFEF) said defender Gerard Pique had recovered from a shoulder injury and trained normally on Monday, while right back Alvaro Arbeloa told reporters he would be fit to face Estonia after recovering from a blow to his right foot.
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