Josh Smith scored 20 points for the Rockets, who trailed 89-88 at the end of the third quarter after Phoenix rallied from an early 18-point deficit.
Eric Bledsoe scored 32 points, one shy of his career high, for the Suns, who enter the All-Star break losers of five of their last six.
Harden ended the first and second quarters with a three-point basket, then opened the fourth with a four-point play that put the Rockets ahead for good. He scored eight in a row during a 2 1/2-minute stretch late in the game.
Harden scored 45 in a loss to Portland on Sunday and has six games of 40-plus points. Houston won for the seventh time in nine games.
at Memphis 95, Brooklyn 86: Zach Randolph had 19 points, Marc Gasol added 14 points and 11 rebounds and the Grizzlies ruined the return to Memphis of former coach Lionel Hollins. Six Grizzlies finished in double figures as Memphis won for the 14th time in 16 games. Mason Plumlee and Alan Anderson each had 15 points for the Nets, who have lost seven of 10.
at Chicago 104, Sacramento 86: Pau Gasol continued his strong play with 26 points and 16 rebounds, Tony Snell had a career-high 24 and Derrick Rose added 23 for the Bulls. It was Gasol's NBA-best 34th double-double of the season and his 13th in a row. Rudy Gay scored 24 for the Kings, who have lost 12 of 14.
Detroit 106, at Charlotte 78: Greg Monroe had 23 points and 12 rebounds, D.J. Augustin added 18 points and the Pistons handed the Hornets their third straight loss. Monroe has recorded at least 20 points and 10 rebounds 48 times since the 2011-12 season, which is the most 20-10 games in the Eastern Conference during that span. Gerald Henderson had 17 points, and Al Jefferson added 13 points and 10 rebounds for Charlotte.