Assistant boss David Kerslake was put in temporary charge for the Sunderland game, with Molde boss Ole Gunnar Solskjaer thought to be Cardiff's first choice as manager.
But if the events of the previous fortnight were having any impact on the players, it certainly did not show early on.
With fans chanting mostly in favour of Mackay rather than against Tan, Cardiff dominated the first 30 minutes.
Steven Caulker and Mutch missed with headers before their sixth-minute opener. Campbell won the ball off Valentin Roberge and fed Mutch, whose shot from the edge of the box was deflected home by Diakite.
After Lee Cattermole had Sunderland's first shot deflected wide by one of his team-mates, Cardiff continued their dominance and Caulker headed at Vito Mannone, who then did well to keep out Peter Whittingham's low free-kick from an angle.
Ki Sung-Yueng forced a save from David Marshall and Jozy Altidore failed to turn the ball in from a yard out at the far post.
Cardiff 2-2 Sunderland: We blew Sunderland away - David Kerslake
That started a flurry of Sunderland chances and Fabio Borini forced two excellent fingertip saves from Marshall at the end of the first half before being replaced by Fletcher at the break because of illness.
After a quiet opening to the second half, the game looked sealed when Mutch took on three players and passed it to former Sunderland striker Campbell, whose first-time shot beat Mannone.
Sunderland, who had earlier gone close through Lee Cattermole, had late hope when Fletcher stretched to convert Emanuele Giaccherini's cross.
They pressed for an unlikely looking equaliser after Colback, Fletcher, Roberge and Giaccherini all squandered chances.
But in the fifth minute of injury time it finally arrived when Colback's deflected effort bamboozled Marshall.
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