The 22-year-old rookie from Lithuania reached double figures for just the fifth time in his career, hitting 7-of-12 shots from the field and making two from long range. His previous high scoring effort had been 17 points on March 1 against Orlando.
Houston blew the game opening by outscoring Phoenix 32-17 in the third period. James Harden added 18 points for the Rockets, who placed all five starters in double figures.
The Rockets made 51 percent from the field and converted 10-of-21 from 3-point range. Wesley Johnson had 15 points to pace the Suns.
Houston moved 1 1/2 games in front of the Los Angeles Lakers in the seventh spot in the Western Conference playoff chase. The Rockets trail sixth-place Golden State by a game.