Kerr blew a penalty, had shots saved and hit a cross-bar -- but set-up teammate Gielnik's goal as the Matildas set another crowd record.
The 10,342-strong attendance at Coopers Stadium is the largest to watch a women's football international in Adelaide.
The previous Adelaide benchmark was 5,168 for a 2006 fixture against China -- the last time the Matildas played in the South Australian capital.
Most came to witness the near-peerless Kerr, who was dynamic despite her misses as Australia swept the two-game series against the Chileans.
Australia's coach Ante Milicic made four changes to his starting line-up from last Saturday's 2-1 win in Sydney before a crowd of 20,029 -- an Australian record for a women's international.
The tinkering had scant impact on the fluency of the Matildas, who produced a first-half domination punctuated by Gielnik's 23rd minute strike.
Played into space by a shrewd Kerr pass, Gielnik's first-time shot somehow eluded Chilean keeper Natalia Campos at the near post.
After a trademark dash forward, Kerr had a shot saved and the ball rebounded to near the edge of the area where Campos, scrapping for possession, brought the Australian down to give away a penalty.
But Kerr's shot from the spot, low to the left, was well-covered by Campos, leaving the hosts 1-0 up at the break despite basking in two-thirds of possession.
Australia continued their command of the world No. 37 Chileans in a second half notable for another Kerr close-call -- in the 48th minute her curling right-footer smacked into the cross-bar.
But despite their general dominance, the world No. 8 Australians almost paid a hefty price for their goal-shooting waste.
And 77 minutes in, Williams had another nervy moment when Chilean Carla Guerrero's speculative 25-metre shot deflected from Kerr and looped toward goal, hitting the top of the cross-bar.