The Blaugrana left-back claims the Ballon d'Or winner did nothing wrong in an alleged altercation with Blancos players after the Copa del Rey clash
Messi was said to have thrown verbal abuse at the Spanish right-back following the side's 1-1 draw in the first leg of their Copa del Rey semi-final on Wednesday.
But Alba was quick to rubbish the claims.
"I didn't see anything wrong with the car park incident. Messi was just annoyed," he told reporters at a sponsorship event.
As well as standing by the 25-year-old, Alba stressed the importance of Barca's second leg against their arch rivals.
"The home game will be crucial. There are a lot of turns left in the tie."