Defending champion Adam Scott sits two shots off the pace after the Australian Masters first-round, but surprise leader Nick Cullen doesn’t plan on disappearing.

Scott and Germany’s Max Kieffer both shot four-under-par rounds of 67 on Thursday morning at Royal Melbourne.

They shared the lead for a time, before 29-year-old South Australian Cullen upstaged them in the afternoon with a six-under 65.

Cullen surged to the lead on the back nine with a chip-in eagle on the par 4 11th, followed by back-to-back birdies.

The left-hander pulled as many as three shots clear late in his round before finishing with a bogey.

Cullen said it was fantastic to be in the same field as US Masters champion and world No.2 Scott.

But having boosted his own confidence by winning the Queensland Open three months ago, Cullen says there’s no reason he can’t stay at the top all tournament.

“It is what you play these events for. It is where you want to be,” he told reporters after Thursday’s round.

“It is exactly where I want to be and hopefully I will be there again tomorrow and around the mark on Sunday.”

Cullen will be out early on Friday, with a 7.30am (AEDT) tee time.

Scott, who was content with his own opening round, won’t start his second round until 12.20pm.

Cancer survivor Jarrod Lyle, who posted a one-over 72 in his first tournament round in 20 months on Thursday, will begin his second at 8.10am.