After going two for seven (including one for five on three-pointers) in the first quarter, he went 10 for 20 the rest of the game, including eight for 14 on 3's, The Associated Press reported.
''That's the confidence I have,'' he said.
''That's the confidence that I've built off of the work I put in. It's more of a mindset.''
Harden, the NBA's leading scorer, entered the game averaging 36.5 points on 38.7 percent shooting, including 27 percent on three-pointers.
''I feel like a broken record sometimes, but he's a master of getting what he wants,'' Houston coach Mike D'Antoni said of Harden.
''I think sometimes he might get bored in the game and tries different stuff.''
Russell Westbrook scored 26 points as the Rockets won their third straight.
Wendell Carter Jr. had 13 points and 16 rebounds for Chicago, which has dropped six of eight.
The Bulls were a woeful four-for-32 shooting from three-point range.
''I know how well we can shoot and tonight we just didn't make them,'' Chicago forward Lauri Markkanen said.
Chicago led 27-20 after one quarter behind eight points from Markkanen and eight Houston turnovers.
The Bulls led by nine points (31-22) early in the second before the Rockets used a 24-7 run to take control and open a 46-38 lead with four minutes left in the first half. Harden had nine points during the run.
Chicago closed within 50-49 at halftime on a three-pointer by Zach LaVine. That was the Bulls second make in 17 first-half attempts from long range. Houston quickly reclaimed control with a 30-9 run in the opening 9:41 of the third, taking an 80-58 advantage.
The Rockets had an 86-67 lead entering the fourth, helped by 7-for-14 shooting from three-pointers range in the third. Harden led the way with 11 points in the quarter.
The Bulls couldn't get closer than 14 points in the fourth quarter.
''I think we did really good in the first half; they just broke it open in the third quarter,'' LaVine said. ''We played a good first half and a bad second half.''
Harden, who has 35 regular-season triple-doubles in his career, had several minutes of garbage time in the fourth quarter to get additional assists, but was unsuccessful before leaving with a little more than three minutes remaining.
''I didn't even know I was one assist away,'' he said. ''I'm happy we won, though.''