Pellistri, who joined the top-flight outfit on loan for the remainder of the season in January, smashed the ball into the roof of the net with half an hour gone to give Granada the lead at Nuevo Los Carmenes.
It was an impressive effort, considering it was just the fourth senior competitive strike of Pellistri's fledgling career, after two for first club Penarol.
He did also score for Granada against Barcelona at the Estadi Olimpic back in February, during an exciting 3-3 draw with the reigning champions.
The Uruguay international played 80 minutes as further goals from Myrto Uzuni and Lucas Boye helped keep the Andalusians' faint hopes of survival alive.