DeMar DeRozan became the first player in NBA history to make game-winning buzzer-beaters on consecutive days.
Giddey acknowledged that the milestone was "cool" after the game, however, made it clear that he would have preferred to walk away with a win.
The Lakers (19-19) climbed back to .500, with their 30-something veterans carrying them in the fourth quarter.
This was the first 40-point game of the season for LeBron and made him the oldest player to put up 40 points and 10 rebounds.
Harden and the Brooklyn Nets returned from a week-long COVID-19 hiatus to beat Los Angeles 122-115 Saturday night.
The rout was on early, as Memphis Grizzlies led by 15 points after the first quarter, 36 after the second and 51 after the third.