MELBOURNE, Nov 16, 2012 (AFP) - World number five Scott lies in third after he posted a second round 70 in difficult, blustery conditions to go seven under with 137.
Between the two Australians is New Zealander Michael Hendry (67-69) who lies in second by two strokes, Scott just one stroke behind him.
Defending champion Ian Poulter of England was two shots further back in joint fourth, at five-under, heading into the weekend rounds.
"I'm in pretty good shape. There's only two people in front of me to get past for me to get the job done," Scott said.
He added that the windy conditions required conservative play, especially when the small greens became rock hard.
"It made it difficult to hold your approach shots on them. Just getting on the green was a struggle today," he said.
Scott added that windy conditions over the final two days would not worry him.
He and leader Guyatt have been rivals on the golf course since they were young amateurs but are good friends off it.
"Matt's worked hard for a number of years and he deserves everything he can get. But I'll be gunning for him," said Scott.
Poulter and Northern Ireland's Graeme McDowell discovered how tricky the relatively short Kingston Heath course can be in a challenging southerly wind.
Poulter had a 72 to be five off the lead and was not pleased with his round.
"I'm not going to stand here laughing. I shot level par and I'm disappointed," he said.
McDowell said he lost his rhythm after the first three holes.
"I got off to a dream start. Three-under after three holes and no comment after that really," the 2010 US Open champion said, after shooting five-over to squeeze into the weekend right on the cut.
McDowell three-putted the fourth hole, was plugged in a trap after trying to lay-up at the sixth and then three-putted seven.
"I just sort of got in a tail spin and lost the feel of my swing a little bit and it knocked the wind out of my sails," the 2010 US Open champion said. "The harder I tried the worse I got. It was just one of those humbling days."
Guyatt, who returned to the game in recent years after taking time out, said he hoped he was up for the challenge over the closing 36 holes.
"I'm relieved to back up with a 69 and pleased I haven't gone the other way, as so many guys with my experience seem to do when they get in contention."
He said he would love the opportunity to play with Scott on Sunday.
Second round scores at the Australian Masters at Kingston Heath (par 72) in Melbourne on Friday (Australia unless stated):
134 - Matthew Guyatt 65-69
136 - Michael Hendry (NZL) 67-69
137 - Adam Scott 67-70
139 - Ian Poulter (ENG) 67-72, Craig Hancock 68-71
140 - David Bransdon 71-69, Matthew Millar 73-67
141 - Paul Gow 68-73
142 - Christopher Campbell 70-72, Gareth Paddison (NZL) 71-71, Chris Gaunt 72-70
143 - Jake Higginbottom 68-75, Richard Green 71-72, Mark Brown (NZL) 72-71, Kalem Richardson 68-75, Cameron Smith 70-73, Oliver Goss 71-72
144 - Stuart Appleby 71-73, Jason Scrivener 71-73, Kim Felton 71-73, Rohan Blizard 69-75, Brett Rankin 72-72
Selected scores
148 - Graeme McDowell (NIR) 71-77, Robert Allenby 72-76, Thomas Petersson (SWE) 72-76
+4 (148) was the final cut, 66 players made the cut