Los Che go into the game having somewhat got away with a woeful defensive display against fellow La Liga side Atletico Madrid in Thursday's Europa League semi-final first leg.
Stoppage-time goals in each half rescued a 4-2 scoreline which, with the benefit of that away double, they will harbour hopes of overturning at the Mestalla next week.
Before that, though, they face a Betis team making a late-season push for a place in the competition next term and Llorente insists they must be on their mettle.
"Against Betis, which is as important as a final, the team will have to play at 200%," he told AS.
"The only solution is that the team must be strong and play as they have shown that they can. We can and must do that."
Malaga travel to sixth-placed Osasuna while Atletico Madrid and Athletic Bilbao return to domestic matters from European competition to face Espanyol and bottom side Racing Santander respectively.
Real Sociedad host Villarreal and Granada take on Getafe.
Sunday's La Liga Fixtures
Monday's La Liga Fixture
Osasuna vs Malaga