The Canaries saw goalkeeper Mark Bunn sent off for handling outside the area to deny a goalscoring opportunity almost immediately after Wes Hoolahan's opener and were soon controversially hit with a penalty.
Sebastien Bassong was flagged by the assistant referee for handball shortly before half-time, Craig Gardner, burying the spot kick, though Sunderland striker Steven Fletcher appeared to be offside. In the second half, Danny Rose appeared to handball similarly in the area but the Black Cats were only penalised with a free kick.
"One I was able to see from my angle was Rose's handball. Initially I wasn't sure it was handball or not but I knew it was in the box.
"I know the sending-off is the biggest decision to put us down to 10 men but the Rose one is clearly in the box and what disappointed me most about the Seb handball was, even if it is handball, the linesman is looking right across the line and makes the decision about the handball but not the offside that was fractions [off], moments before.
"You really want to be clear about what you say and, to be honest, I'm not certain on handballs at the moment."
Despite the controversy, Norwich held on and now sit a comfortable nine points above the drop zone with eight games remaining and Hughton added: "I think you've got to give credit to a group of lads that were desperate to get something out of this game.
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"The disappointing thing is, I think, with 11 men we would have given them a really good game."
Sunderland manager Martin O'Neill was left disheartened with his side's failure to establish a gap between themselves and the relegation zone, meanwhile, admitting: "The second-half performance was very disappointing. With the extra man we should have tried to make it count and frustrating for the number of chances we didn't create, that was very disappointing.
"I have not seen one incident back yet," he added, "but I've been assured that we got a bit of luck with Danny Rose's and one or two decisions.
"We had an opportunity there to go and get three points, it's been difficult all season for us, but we have games still to play, tough matches every one of them. The whole league's been tough for us."