Inbee Park was flawless in a round of 5-under 66 to take the early lead as women's golf returned to the Olympics for the first time since 1900.
Park felt more nervous than usual for a couple of reasons. South Korea is the dominant nation in women's golf and the Olympics is so big at home there is a talk of a podium sweep at Olympic Golf Course. Park is among four South Koreans in the 60-player field. Park also has not played against top competition for two months because of thumb injury.
But in warm, windy conditions, Park looked every bit the player who has won seven majors and who earlier this year qualified for the Hall of Fame. Not only did she play without a bogey, she shot 66 despite missing six birdie chances of 10 feet or under.
Lydia Ko of New Zealand was at 1 under through 12 holes. Ko headed into Rio as the favorite, as she is most weeks on the LPGA Tour.
She already has won four times this year, including her second major at the ANA Inspiration in California, and she was runner-up to Brooke Henderson of Canada in the KPMG Women's PGA Championship.
What's special about this week is playing for the flag, which she has never done as a professional.
Ko is not eligible for the Solheim Cup, which is for Americans and Europeans. New Zealand does not have the depth to form a team for the International Crown, which was the closest event golf had to the Olympics before the Olympics came along.
There is no team component to golf in the Rio de Janeiro Olympics, so this week really is no different. It just feels that way.
"Even though there I'm the only New Zealand woman golfer in this week, I think it's not more about our sport, but just every other athlete and every other athlete from New Zealand," Ko said before competition. "I do feel that team vibe. I heard that some of the athletes might come out and watch me play, and I think even more then I'll be super excited to see the Silver Fern and see all the logos."
Lexi Thompson was the low American so far at 68 on Wednesday.