Harden got 36 points and 13 assists and shot six of 16 from beyond the arc for the Rockets.
For the injury-ridden Warriors – last season's NBA finalists – it was a sixth defeat in eight games.
The Pistons have now won their last eight games against the Knicks.
The latest loss drops the Knicks to an NBA-worst of 1-7, while the Pistons are now 4-5 and lie in eighth place in the Eastern Conference.
In Atlanta the Hawks lost 113-93 to the Chicago Bulls, in a game that saw Tomas Satoransky score a career-high 27 points.
It was just the Bulls' third win in nine games this season and they lie in 11th place in the East, two places below the Hawks.
Atlanta's coach Lloyd Pierce did not mince his words after the match. "The only positive from this game: It's over," he said. "We don't have to worry about it anymore."
The Dallas Mavericks got over the line 107-106 against the Orlando Magic, in Utah the Jazz won 106-104 over the Philadelphia 76ers and the Los Angeles Clippers lost 129-124 at home to the Milwaukee Bucks.