Brent Newdick was slightly off his best in a few of his events as he strove to improve on his 23rd placing in the decathlon in Berlin two years ago.
He was away to a confident start by winning his heat of the 100m in 11.00s.
"The time wasn't quite where I wanted it to be, but everyone was down a bit," reflected Newdick.
In the long jump Newdick cleared 7.31m in his first attempt, followed by 7.14m and a no jump.
The Delhi Commonwealth Games decathlon silver medallist was out to 13.75m in the first round of the shot put. He fouled his second attempt and achieved 13.25m on his third attempt.