The 1977 NYC Mayoral election, A Contest between Ed Koch and Mario Cuomo, a rematch from the Primary runoff ended with the same Result, Koch winning and this time officially becoming mayor.
A Self described "Liberal with Sanity," Koch won thanks to Strong support from the city's Upscale WASP, Jewish, African American, Hispanic, and eastern European populations, in addition to his proposal for cutting waste in city government, (https://www.youtube.com/watch?v=AUPdRU-xSyc)
By Contrast Cuomo mainly had support from Catholics, specifically Italian Catholics whom propelled him to a strong second place showing both in the Primary Runoff and in the general; coming ahead of the Republican and Conservative candidates.
The First round in the primary ws a veritable heat-map of NYCs' population at the time, with Koch winning on Manhattan's upscale, east side Cuomo winning in the Italian areas, Beame in the Eastern European areas,
Abzug in the Liberal Jewish West Side, Sutton in NYC's African American Areas, and Badillo carrying the City's hispanic population
Likewise the primary Runoff was a precursor to the coalitions seen in the General Election with a few slight diferences, such as Cuomo's performance with African Americans in the outer boroughs of Queens and Brooklyn worsening in the general as compared to the runoff.
This was also the last time an incumbent mayor of NYC lost Renomination, as due to a chaotic term where he was unable to deal with the city's many growing problems, highlighted by the 1977 NYC blackout, incumbent Abraham Beame would lose in the jungle to Cuomo and Koch