Making his Olympic debut, Blake held every service game and earned the only break of the match for a 5-3 lead in the first set. The 28-year-old American faced a set point at 5-6 in the second set but held, then hit five winners in the tiebreaker.
When Blake smacked an ace on match point, he threw a fist and shouted "Yeah!" as the impartial stadium crowd of 4,000 applauded.
"Definitely more nerves than a normal match," Blake said. "I tend to not really get nervous when I'm out on a tennis court, but today was a little different."
Twice during the match small clusters of fans chanted "U-S-A!" With Andy Roddick skipping the Olympics, Blake is the highest-seeded American in the men's draw at No. 8.
The start of the tournament was delayed 2½ hours because of rain, then began under thick smog. While Blake waited to play, he watched other events on TV, including Michael Phelps' record performance to win a gold medal in the 400-meter individual medley.
Nine matches were completed, 10 suspended and 26 postponed, which means a heavy backlog for the tournament.
"Watching Michael Phelps set a world record, it was something that was special to me because it made me realize how many people are inspired by him, and that I'm now in the position to have that opportunity to go out there and get a medal for my country," Blake said. "Today was hopefully the first step toward that."
Chile's Fernando Gonzalez, a singles bronze and doubles gold medallist four years ago in Athens, also reached the second round with a 6-4, 6-4 defeat of China's Sun Peng.
Tennis is celebrating the 20th anniversary of its return to the Olympic family in Seoul.
Information from Reuters and The Associated Press was used in this report.