Marcus Fraser holds a three-shot lead after the first round and Justin Rose conjured up a historic hole in one when golf made a long-awaited return to the Olympic Games on Thursday.
Not since 1904 had golf been contested in the Olympics, but the sport made a comeback 112 years later at the purpose-built Barra da Tijuca on day five of the Rio Games.
It was Australian Fraser who made the early rush for gold, carding an eight-under-par 63 - the best round at an Olympics - to top the leaderboard.
Canada's Graham DeLaet had set the clubhouse lead with a brilliant 66 and Open champion Henrik Stenson joined him after the Swede finished with a sixth birdie of his impressive opening round to sit ominously in a share for second.
Great Britain's Rose also made a big impact, punching the air after becoming the first golfer to hole an ace in the Olympics at the 191-yard par-three fourth and is among five players on four under.
Brazilian Adilson da Silva had the honour of hitting the first Olympic tee shot for well over a century on a memorable day which so many of the big golfing names missed due to concerns over the Zika virus.
ROUND OF THE DAY
With Jason Day, Adam Scott and Marc Leishman withdrawing from the Games, Fraser grasped his opportunity to fly the flag for Australia.
The world number 90 birdied the par-five first hole and recovered from a bogey at the next to make a further four gains and hit the turn in 31.
A further four birdies then enabled Fraser to put open up a healthy advantage going into the second round on Friday.
SHOT OF THE DAY
Da Silva's tee shot was a special moment, but there can be no doubt that 2013 U.S. Open champion Rose produced the shot of the day.
The roar could be heard around the course when the Englishman's iron shot rolled towards the pin and dropped, prompted high fives all around.
"It has been on my mind a lot. It was a privilege and a huge responsibility. It's hard not to get emotional." - tearful Brazilian Adilson da Silva, who finished one over for the day, after hitting the opening tee shot in the first Olympic golf competition for 112 years.
"Very rarely do you get to represent your country. I feel very fortunate to be in this position. I am pinching myself, it is a surreal experience that is for sure." - Fraser following his blistering start.
"I have got to complete all four rounds so I can say I am officially an Olympian. It is an amazing feeling. I want to smile all the time. The other night I wanted to cry because golf is in the Olympics and for the first time in my life I get to be the hero." Bubba Watson of the United States after carding a two-over 73.