Callum Paterson scored twice and Joe Ralls and substitute Anthony Pilkington were also on target as Cardiff moved back into the Sky Bet Championship promotion places ahead of the afternoon kick-offs.
Sunderland’s miserable day extended to a red card for Didier Ndong four minutes after the break with the score 1-0, the Gabon midfielder dismissed for a poor over-the-ball challenge on Junior Hoilett.
Coleman enjoyed plenty of special moments at the Cardiff City Stadium during a six-year reign as Wales manager which ended when he took over Sunderland in November.
Belgium, then ranked the second best team in the world, were beaten at Cardiff on Coleman’s watch.
But his battle to prevent bottom-club Sunderland sliding towards relegation may prove an even bigger task for the Welshman.
What attacking threat there was in the first half came from a Cardiff side who had their lost their four previous games.
A fifth would represent the Bluebirds’ worst run in the league for 20 years, while veteran manager Neil Warnock had not lost five in a row since 1995.
Cardiff’s early probing saw Paterson head a Ralls free-kick into the arms of Robbin Ruiter, before the Black Cats managed a rare foray which saw George Honeyman blaze over.
The prominent Ralls and Hoilett failed to get the better of Ruiter, while Kenneth Zohore’s header deflected on to the roof of the net.
The contest took an unswerving path right at the start of the second half when Paterson met Ralls’ corner inside 90 seconds of the re-start.
Two minutes later referee Andy Madley made the correct call as Ndong stretched and left his studs on Hoilett’s ankle.
There seemed no way back for Sunderland and so it proved as Cardiff produced the best move of the match.
Neat passing released Zohore down the left and his cross was swept home by the supporting Ralls in the 55th minute.
Zohore almost added a third when Yanic Wildschut, freshly arrived on loan from Norwich, weaved his way and set up a shooting opportunity which Ruiter grabbed at the second attempt.
Sunderland came close to a lifeline when Bruno Manga almost sliced into his own net.
But Paterson punished them again when Zohore’s free-kick deflected into his path and he fired home left-footed from 18 yards with 10 minutes remaining.
Sunderland’s heaviest defeat under Coleman was confirmed when Wildschut set up fellow substitute Pilkington for the simplest of finishes in stoppage time.
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