The relegation six-pointer at the Stadium of Light turned into a nightmare for Ole Gunnar Solskjaer's side as a double from in-form striker Connor Wickham, a penalty from Fabio Borini and a goal for substitute Emanuele Giaccherini lifted Sunderland out of the drop zone.
However, the game was not without controversy as referee Phil Dowd awarded Sunderland their penalty when Cala pulled Wickham's shirt, despite initially allowing the advantage.
Midfielder Whittingham was quick to deny the decision had any bearing on the result and admitted the Welsh outfit were "not good enough".
"I'm not sure about the ins and outs of the penalty," he is quoted as saying by WalesOnline. "Look, the referee gave it and once he has given it there's not a lot anyone else can do about it.
"The sending off was a huge moment, but even before that happened I just don't really think we were good enough.
"They got their first goal and then obviously the sending off did not help us, but we were just not good enough at all."
Despite the lacklustre nature of Cardiff's performance, Whittingham insists the whole squad were motivated ahead of the contest.
He added: "We were definitely up for the game. The boys had been looking forward to it for the whole week. That was not a problem at all.
"But in all honesty I'm not sure anyone could put their finger on what happened to us. Sure the sending off did not help, but we were simply not good enough even before that."
The result leaves Cardiff rooted to the bottom of the Premier League, two points adrift of Sunderland with just two games remaining to preserve their top-flight status.
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