But the nerves of being announced as "defending champion" on the first tee at The Lakes Golf Club got the better of the Sydney youngster as he began quadruple-bogey (8), double-bogey (6), bogey (5).

"As soon as I heard my name on the on the first my legs were jelly," Davis said.

"I was actually fine until they called out my name and the crowd started cheering.

"I probably tried to swing too hard."

But showing true grit, Davis gathered himself and rode a wave of steady pars before rattling off four straight birdies from the 8th hole and, save for a bogey at the 15th, he salvaged some dignity to sign for a four-over-par 76.

The 23-year-old Davis sits a distant nine shots back of first-round leader Byeong Hun An (67), who has a one-shot buffer over locals Matt Jager and amateur David Micheluzzi (both 68).

"As soon as I heard my name on the on the first my legs were jelly … I was actually fine until they called out my name and the crowd started cheering.” – Cameron Davis

"It could have been such a bad round; I hung in there well," Davis said.

"I'm still disappointed; I wanted to have a really good round today but it's a lot better than it could have been.

"After the third (hole) I started hitting greens and that was all it really took to settle me.

"I knew I had birdie opportunities on the back nine, regardless of how hard the wind was blowing."

Although well behind the leader, Davis refused to rule himself out of winning the Open.

"Other than that start I played a pretty good round of golf; I know it's still there," Davis said.

"I'm looking forward to the challenge; people have had (poor starts) before and still won golf tournaments.

"The only way I'm going to win is by not thinking about (today) and letting it happen.

"If I shoot a really good score for three days you never know what could happen."