Juve lost 2-1 to Real Madrid at the Bernabeu on Wednesday night as a brace from Cristiano Ronaldo rendered Llorente's 22nd-minute equaliser a mere consolation.
The sending off of Giorgio Chiellini for an apparent arm in the face of Ronaldo early in the second half gave the Italians a mountain to climb and they now sit seven points behind Madrid and two behind Galatasaray in Group B.
"Unfortunately we know we can't afford any more slip-ups in the Champions League," Llorente told www.juventus.com.
"We put in a good performance and had several chances to score but the referee changed the game when he showed Chiellini that red card.
"Giorgio didn't deserve to be sent off for that, it wasn't such a bad foul on Ronaldo."
Madrid are the visitors to Turin for matchday four on November 5 and Claudio Marchisio is in no doubt of the importance of that contest.
"The return match against Real at Juventus Stadium will be decisive," he said.
"It was really hard out there in the second half today. Playing a man light after Chiellini was unfairly sent off, and against the quality of this Real side, we had our work cut out.
"But despite that we still managed to do very well. We responded after they got themselves in front and asked questions of them up front."
Juve also host Copenhagen before travelling to Turkey for their final group game and, despite the prospect of that testing finale, Marchisio remains confident.
"It's a tough path ahead now but we can take heart from our performance tonight," he added.