The veteran put on a stunning 15-minute display in front of goal during the landslide victory at San Mames, doubling the Basques' lead with a precise header before volleying home and then completing his treble by tucking away a penalty.
But the 34-year-old said that although he was elated with his personal exploits, they would ultimately count for little if they cannot defend their lead in the return leg at Camp Nou on Monday.
"If we manage to lifty the trophy on Monday then it could be the happiest night I’ve had," Aduriz told reporters. "We’re very satisfied with the result.
"We know how difficult it is to beat Barcelona and it’s practically impossible for many teams manage to put four past them. All of the goals have been important and satisfying; out on the pitch, we just try to continue with the same willingness and determination.
"But we can’t think that a four-goal advantage will be enough at Barca’s ground. The return leg is going to be tough."
The once-capped Spain international is now in his fourth season at Athletic and will hope to begin it with his first piece of silverware at the club.