Betis are at the foot of the Primera Division and go into Saturday's game after a harrowing 5-1 defeat at Real Sociedad, which was a baptism of fire for Garrido in his first league game in charge of Betis.
The match with Almeria, who are three points above Betis but occupy the final position in the relegation zone, is the coach's first game at home in the league and he does not need reminding of its significance.
"Everyone knows that this game is fundamental," he told reporters.
"Everyone involved with the club, from the players, coaching staff, directors and fans, knows that it's vital. Everyone has no choice but to give 100 per cent for Betis. We are all focused on giving everything in this game.
"The players know that they have to play the game of their lives, and the fans know we must stick together in a game in which we are playing for half our lives."
Betis fans have been vocal in their criticism of the team's recent performances but Garrido expects them to be in full voice on Saturday.
He added: "I'm sure it will be a great atmosphere, where every person in the stadium is supporting the team. The fans know how important the game is and they are aware of the role they could play in supporting the team."
Garrido admitted that defender Antonio Amaya would not be able to make it back from a muscle strain in time, but was confident Ruben Castro, who played 90 minutes against Real Sociedad, was close returning to full fitness following a back injury.
He said: "He's recovered and now he' in a process of getting better little by little. Tomorrow he'll be in as good a shape as he can be right now, in the right condition to produce a good performance."
Almeria go into the game after drawing 0-0 at home to Espanyol last week, a result that was made worse by the fact midfielder Verza missed a first-half penalty.
Francisco Javier Rodriguez's side will be without top scorer Rodri, who is still suffering from an ankle problem he sustained a month ago against Real Madrid.
Garrido praised his team's opponents for how they have turned things round after failing to win a match in their opening 10 games.
"They looked dead and buried and everyone thought they were certain to go down," he said.
"But they worked hard and turned the situation around, they managed to overcome their difficulties, and they can serve as inspiration to us."