Garcia's dagger drops Real Betis
Samuel netted midway through six minutes of stoppage time to give Malaga the lead for the third time in the match and this time battling Betis could not find a response as Bernd Schuster's men picked up their first win in six matches.
To add insult to injury for Betis, the extra time was added because of a serious-looking head blow suffered by their centre-back Damien Perquis at the start of the second half that required lengthy treatment before he was taken away in an ambulance.
The loss of Perquis and Samuel's late clincher soured what had been a promising performance from Betis, who had twice fought back from goals down to level at 2-2 and had chances to get more.
Roque Santa Cruz, playing against his former club, and Eliseu Pereira twice put Malaga ahead in either half but Betis levelled through Joan Verdu and Jordi Figueras, only for the visitors to end up empty-handed right at the end.
Dorlan Pabon's rocket late in the first half was enough to give under-fire coach Miroslav Djukic some breathing space.
Piti, who scored 18 goals for Rayo Vallecano last term, missed the last two games through injury but he climbed off the bench in the 78th minute on Sunday before curling home a stoppage-time winner from 25 yards out.
That helped Granada follow in the footsteps of Barcelona and Real Madrid as the only clubs to have beaten Levante this season and denied their opponents the chance to move level with fourth-placed Villarreal on 20 points.