Some folks were upset Cardi B won Album of the Year at the BET Awards -- but not Mary J. Blige ... whose opinion MIGHT just matter more than yours.
The Queen of Hip-Hop Soul was leaving TAO Sunday night in Hollywood after the jam-packed show -- in which Mary herself received a Lifetime Achievement award -- and she told us how she felt about CB getting the big prize over the other nominated artists.
Check it out -- Mary's got nothin' but love for Cardi, whom she thinks "deserved that s***!" ... no questions asked. Some peeps thought Meek Mill, Travis Scott or Ella Mai were more worthy, but Mary wasn't hearing it. It's clear ... Cardi's got her heart.
We also had to congratulate MJB on the big award she walked away with -- for which she did her OWN damn tribute, alongside Lil' Kim and others. It was absolutely epic, and if Cardi deserved AOTY ... Mary absolutely deserved a lifetime achievement.
Mary opened up to our camera guy about how it felt to be honored ... sounds like it left a bigger impact than some might have thought.