Abraham birdied the first and second holes to move to 11 under to hold a one-shot lead at the Grange Golf Club.
Chile's Joaquin Niemann shot four birdies in his first nine holes to move to 10 under.
Englishman Sam Horsfield is nine under, with Carlos Ortiz eight under.
Major winners Jon Rahm, Brooks Koepka and Bubba Watson are at five under.
Watson, who won the US Masters in 2012 and 2014, made an eagle and three birdies in a seven-hole stretch.
Australia's Cam Smith is also in the midst of a stellar round as the fan favourite makes a belated move up the leaderboard.
Smith is four under for the day and three under for the tournament alongside compatriot Lucas Herbert.
Fellow Australians Marc Leishman (two under) and Matt Jones (five over) comprise the Ripper GC, whose hopes of successfully defending their Adelaide team title are all but over.
The all-Australian team is a combined four under, some 14 shots behind Fireballs GC captained by Spanish great Sergio Garcia and featuring individual pacesetter Ancer.
12°C