An extra-time goal from Alex Berenguer sealed Athletic Bilbao's place in a second successive Copa del Rey final when they beat Levante 2-1 after extra time on Thursday to secure a 3-2 aggregate victory.
Garcia then equalised from the penalty spot on the half hour after being wrestled to the ground by Oscar Duarte when he appeared poised to tap in Inaki Williams's cross.
The Basque side looked the more likely side in the second half, but were unable to find the breakthrough in normal time before Berenguer's long-range effort deflected off Nikola Vukcevic and flew into the net eight minutes from the end of the extra period.
Bilbao coach Marcelino Garcia, who won the 2019 Copa while in charge of Valencia, could complete a unique hat-trick of back-to-back cup triumphs.
Barcelona secured their place in April's showpiece with an extra-time win on Wednesday.