More than a decade after her decisive golden goal, the 106-game veteran, and current Australian captain, hopes to inflict more discomfort on New Zealand in Adelaide tomorrow now her own aches and pains have subsided.
McMahon, Australia's premier goal attack, is understandably showing the signs of depreciation expected after 12 ultra-competitive years at the elite level, not that her influence in the three-test series against New Zealand should be understated.
A persistent knee injury two years ago was McMahon's first sign of mortality and now, at 33, those knocks she once brushed off with a grimace are requiring rest and rehabilitation.
Injuries limited her contribution as the Melbourne Vixens meekly surrendered the trans-Tasman netball crown this season - her shooting statistics detailed the former champion's decline to sixth place.
McMahon shot at just 79.1 per cent and recorded 235 goals, compared to her 2009 season haul of 339.
A badly bruised thigh during training then limited her to a third test cameo against Jamaica last week, where McMahon announced her return with an encouraging 21 from 25 attempts.
McMahon is guaranteed to see more game time in the annual trans-Tasman series opener at the Adelaide Entertainment Centre tomorrow (5.23pmNZT).
And where she is concerned the Silver Ferns players and management clearly subscribe to the sporting theory of form being temporary, but class permanent.
When it was suggested McMahon's disrupted year might be an advantage for her side, coach Ruth Aitken swiftly disagreed.
"She's a big game player so until it becomes a big game she can be a bit up and down, but I know she will come to the party when it counts," she said.
Defender Joline Henry also saw no significance in McMahon's subdued season.
"I don't think it'll mean a lot to her. She'll be just as strong as she was had she not had the injuries.
"Sharelle's as amazing as she ever was but I back my defensive line."
While the midcourt battle plays a significant influence on the outcome, the focus will inevitably fall on the shooting circle to see which combination can capitalise on possession.
The peerless Irene van Dyk obviously shoulders the scoring responsibility for the Silver Ferns, Australia's major contributor is not as clear cut.
While McMahon's presence tomorrow is a given her Vixens teammate Natalie Medhurst and the NSW Swifts duo of Catherine Cox and Susan Pratley are vying for the support act with outsider Kate Beveridge.
None of the quartet had stunning returns in the trans-Tasman league - Pratley had the superior accuracy rate of 81.8 per cent; Cox just 74.6.
Beveridge (69.4) was benched for the pivotal stages of Adelaide's march to the title while Medhurst (80.8) could have the inside running based on her combination with McMahon in Melbourne.
Whichever option Plummer fields, Henry said those shooting stats hardly equated to a bonus for the Silver Ferns.
"Shooters have off-day like anybody else. They're (Cox and Pratley) are pretty lethal with the Swifts," she said.
"They went through the round robin unbeaten, I don't think we can take anything away from that."
But she was still confident the defensive unit of Casey Williams, Katrina Grant, Leana de Bruin and Anna Scarlett could curb the Australians.
"We've got lots of tall bodies with lots of long limbs," said Henry, who has converted to wing defence.
"We want to be making the most of that, making sure we disrupt their vision. It's an area we've worked a lot on, how we defend the shot."
McMahon, meanwhile, is looking forward to a challenge frustrated by the need to carefully monitor her court time and recovery as she eyes the Delhi Commonwealth Games and next year's defence of the world crown in Singapore.
She felt up to playing tomorrow and then next week's tests in Wellington and Auckland but accepted she was no longer the physical specimen that had the Ferns despairing all those years ago in Christchurch.
"I had a bit of wear in my knee that kept me out of the 2008 international season and it just means that I can't do some of the things I could 10 years ago."
