There is a reporting mistake on this card from last summer. In the bout between Ricardo Calzada and Jeff Watkins it was Watkins who went down in the first, not Calzada. Unfortunately, I can find no print media accounts to verify this, but I'm watching it right now on a saved internet ppv broadcast and Calzada knocks down Watkins with a right hand about 30 seconds into round 1. It occurs at about 1 hour, 13 minutes, and 6 seconds into the ppv. Watkins is up on a count of 2.
If an editor wishes to confirm this, I will give him the link and password necessary to view the fight.