Carlos Correa's walk-off dinger to even up the ALCS on Sunday was bigger than baseball ... 'cause the MLB star dedicated the home run to one of his biggest fans battling cancer.
Jalen Garcia is a teenage Houston Astros super fan who has been bravely battling Osteosarcoma -- a type of bone cancer -- since he was 13, according to the Laredo Morning Times.
The 25-year-old shortstop and his fiancee, Daniella Rodriguez, met the big-time fan at a hospital in Houston on Friday ... and Correa was so moved by the visit, he wanted to do something extra special that Garcia would never forget.