John Macharia, 28, plunged to his death from a multi-storey apartment block in Nairobi after David Moyes' men suffered a second home defeat in four days, denting the champions' chance of retaining their Premier League title.
"Macharia jumped from seventh floor of an apartment at Pipeline Estate after realising that his team Manchester United lost 1-0 to Newcastle at Old Trafford and committed suicide," Nairobi's County Police Commander Benson Kibui told Reuters.
Newcastle's first win at Old Trafford since February 1972 means the champions are now 13 points adrift of league leaders Arsenal.
Macharia's death is reminiscent of the suicide by a Kenyan Arsenal fan in 2009. Suleiman Omondi, 29, was found hanging in his flat after the Gunners were trounced 3-1 by Manchester United in the second leg of a Champions League semi-final game.
Kibui urged football-obsessed Kenyan fans to support local teams rather than foreign clubs who do not have a link to the east African nation that is best known in the sporting world for producing middle and long-distance champion runners.
"The football fans should enjoy the matches... but they should not commit suicide since life is very precious," Kibui added.
(Reporting Humphrey Malalo; Writing by Drazen Jorgic, editing by Pritha Sarkar)
