Season 51, Game 18
San Antonio 90, New Orleans 107
11-7, 4th in the West
I know the record books will say otherwise, but in my recollections, the Spurs have only one exactly one game in New Orleans: Game 7 of the 2008 Western Conference Semifinals. (And this only after getting crushed in Games 1, 2, and 5.)
The most egregious of these losses was in 2015, when all the Spurs had to do was win one single game in the Big Easy to secure the 2-seed in the West and credibly defend their title.