The problem is that the conditions of victory, the way the battle is set up, and how the fight is staged hasn't been specified. Without those, this entire debate is pointless.
And the conditions for victory are critical because victory doesn't explicitly mean one side must destroy the other. If you compared the Rebel blockade runner to an ISD, victory may have been that Princess Leia's ship escaped the ISD... not that it could destroy the ISD.
All this hostility, complaints, demands for proof, and false assumptions are not going to get anywhere. You can't make a clear answer w/out all the pieces to make an effective argument. We don't know whether the SF could survive an attack by the DS, but I really don't care if it can't. I would still prefer a SF over a DS.