Sunderland boss Tony Mowbray said:
"I think inconsistency is a problem for us, we can be good in spells and poor in other spells.
"We didn't start well and for 25 minutes showed them too much respect and they picked us off really.
"We didn't do well enough out of possession in the first-half and we've got to keep going and keep working.
"We all have to get better. We are disappointed. We had a good win away from home and couldn't follow it up. So we feel deflated."
Cardiff City interim boss Mark Hudson told BBC Radio Wales Sport:
"I think it was a deserved win, in the first-half we showed real quality, it was the best we have played in a half.
"The only thing missing was a goal in the first-half and we came back in and backed up what we did in the first-half by getting the goal.
"We knew then we would need to suffer a bit late-on as the away team after after a long week, but we've dug-in and shown what we are made of.
"I told Mark Harris at half-time to keep going and he would get his chance and I was delighted when he did."