Whelan stood down from his role of chairman this week after two decades and handed the reins to his 23-year-old grandson, who watched on as Kim Bo-kyung scored the decisive goal after just eight minutes.
The result moves Wigan up one place to 22nd, six points from safety, while Norwich spurned the chance to go second.
City's county rivals Ipswich Town suffered a blow of their own, going down 2-1 at Leeds United as Daryl Murphy's late penalty was saved.
All three goals came in a seven-minute second-half spell, in which Alex Mowatt gave the hosts the lead at Elland Road, Freddie Sears levelled, and Billy Sharp netted what proved to be the winner.
Murphy fluffed his lines from the spot in the closing stages, with Marco Silvestri - who should have done better with Sears' equaliser - making a good save to leave Ipswich outside of the top six.
Elsewhere, it was an unhappy return to Birmingham City for Lee Clark, who saw his Blackpool side slump to a 1-0 defeat at St Andrew's, and Blackburn Rovers won 2-1 at Sheffield Wednesday.
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