Blake, who spent last season with Portland and the Los Angeles Clippers, came off the bench to score 10 points, including the final bucket off an assist from Kobe Bryant.
Bryant scored 27 points and had five rebounds and seven assists in 37 minutes. Bryant was 8-of-20 from the field, but hit 11-of-12 free throws.
Kevin Martin scored 26 points in his Houston debut. Aaron Brooks added 24 points and Luis Scola finished with 18 points and 16 rebounds.
Yao Ming scored nine points and had 11 rebounds in 23 minutes. Yao saw his first significant playing time since the 2008-2009 playoffs when he broke his foot.
Houston led 62-51 at halftime but Los Angeles outscored the Rockets 35-28 in the fourth quarter.