With two rounds left, the fifth-placed GIANTS remain a mathematical chance of qualifying for the top four after eliminating the Thunderbirds from contention on Sunday at Adelaide's Priceline Stadium.
Wins against third-placed West Coast Fever and the NSW Swifts (fourth) in the next fortnight are a must and they would also need a percentage boost to sneak into an elimination final.
Outstanding goal attack Kiera Austin (30 goals, 13 feeds and two gains) ensured the GIANTS will at least be in the conversation.
"We knew there was a lot on the line for us," Austin said.
"And Adelaide is such a great team and they've grown such good combinations so we knew they would be really tough."
Parmenter enjoyed a breakthrough season in 2019 and Australian greats Laura Geitz and Liz Ellis have both tipped Parmenter for national team selection.
It will aid her cause that the strong performance against the Thunderbirds showcased her versatility at wing defence, wing attack and centre where she eased the load on Jamie-Lee Price.
The Thunderbirds brought their A-game in defence but were eventually worn down by the well-organised GIANTS.
Having to win each of their last three games to be any chance of reaching the finals, the Thunderbirds needed to lift to cover for the absence of co-captain Chelsea Pitman.
It has been a hectic 2020 for England stalwart Pitman who has a history of calf problems and was rested from the clash.
The vacancy at wing attack created an opportunity for Georgie Horjus but the Thunderbirds' standout was Maisie Nankivell, another 2020 breakout player who had a big first half impact with and without the ball.
Nankivell's defence made the GIANTS work hard in transition and they needed the drive of Austin to muscle their way to a 28-23 halftime lead.
Score breakdown
Q1: Thunderbirds 13 v GIANTS 10
Q2: Thunderbirds 10 v GIANTS 18
Q3: Thunderbirds 13 v GIANTS 20
Q4: Thunderbirds 18 v GIANTS 16
Nissan Player of The Match – Kiera Austin (GIANTS Netball)
Thunderbirds shooting statistics
Sasha Glasgow: Total points 5 - G1 5/7 (71%) G2 0/2 (0%)
Georgie Horjus: Total points 10 - G1 2/2 (100%) G2 3/9 (33%)
Lenize Potgieter: Total points 41 - G1 41/46 (89%) G2 0/1 (0%)
GIANTS shooting statistics
Kiera Austin: Total points 34 - G1 26/32 (81%) G2 4/9 44(%)
Jo Harten: Total points 30 - G1 26/33 (79%) G2 2/4 (50%)
Thunderbirds starting seven: GS – Lenize Potgieter GA – Sasha Glasgow WA – Georgie Horjus C – Maisie Nankivell WD – Shadine van der Merwe GD – Layla Guscoth GK – Shamera Sterling
GIANTS starting seven: GS – Jo Harten GA – Kiera Austin WA – Maddie Hay C –Jamie-Lee Price WD – Amy Parmenter GD – Kristiana Manu’a GK – Sam Poolman