The Black Cats were forced to play out the majority of the match a man light after George McCartney was dismissed for tugging back Shaun Wright-Phillips when he was trying to latch on to a through ball on the edge of the Sunderland box.
Assistant referee Mo Matadar awarded the foul and then instructed referee Steve Tanner to dismiss the defender.
And under pressure coach Sbragia clearly felt the the decision had cost his team the game.
"I think it was vital," Sbragia told Sky Sports. "It changed the game completely. We were doing reasonably well, were quite comfortable in the game and for some reason he's given a sending off.
"At the end of the day the goalkeeper has got the ball in his hands so Wright-Phillips was never going to get it. The linesman made the decision so I'm really disappointed."
GripeMartin Fulop went on to save a tamely struck Robinho penalty and, though Sbragia had no complaints with that award following a reckless challenge from Steed Malbranque, he was unhappy with the eventual match winner.
Micah Richards it was who rose to head the ball home from a free-kick just short of the hour mark, but Sbragia has questioned the award of the set-piece as Kenwyne Jones tracked back to challenge Valeri Bojinov.
"I don't think it's a free-kick," Sbragia added. "I think he's let it run and he's come across Kenwyne and lost the ball.
"But defensively it was a poor goal from our point of view. We've let him come in between us and get a free header and you can't give Richards a free header from there.
"It would have been nice to get something here today, but I don't think we've moved in the table.
"It would've been nice to go into the international break with a point or three points but it's not happened. We've got the West Ham game in a couple of weeks and we know it will be very difficult.
"I think we've got to stay together, work hard and get some points on the board."