The Argentine coach was in awe with the striker's display against the Portuguese side and stated that he will sit down with the club's officials to discuss his future
The 27-year-old scored the decisive goal in the dying stages of the match after he had set up Ibai and Susaeta during the first half.
"Llorente played like I had never seen since I have been at this club," he said after the game. "Moreover, this was our smoothest match, as far as collective play goes.
"I was very happy for my players. I congratulated them and told them they absolutely deserved this.
"These kind of matches create in the players a huge sense of responsibility because they want to make the fans happy and are afraid to disappoint them. So we are all relieved to go through."
Bielsa is understood to be the favourite to take over from Pep Guardiola at Barcelona if the Spaniard steps down at the end of the season, and the 56-year-old revealed that he is set to discuss his future with Athletic.
"When the season comes to an end, the club and I will make that matter a priority," Bielsa said.