Golden State took a 6-0 lead and never trailed the Blazers to win their third game in a row over Portland, while shooting just 40.9 percent at the Rose Garden.
"Everybody is always worried about offense, but it's defense that wins ball games," said Richardson. "We wanted to come out and win this game. I was feeling good in the first quarter."
Sebastian Telfair led Portland with 20 points and Darius Miles added 15 and eight rebounds.
Zach Randolph had a double-double with 13 points and 13 rebounds for the Trail Blazers, which has lost two of their last three.