But Tomljanovic, fascinated like the rest of the tennis world about what Williams may still be able to deliver - or not - on Centre Court on Tuesday, is pretty sure the 'GOAT' isn't here to make up the numbers and really does have an eighth title in her sights.
On one spectacular night of high emotion in New York, Tomljanovic enjoyed the highlight of her career in September 2022 when she brought down the curtain on Williams' matchless reign with that celebrated win at the US Open.
At least she thought she had.
For now Serena's back after nearly four years, having accepted a singles wildcard at the tournament she won seven times, leaving veteran Tomljanovic thrilled that it's her 20-year-old pal Joint who could now replace her as the answer to the quiz question: 'who's the last person to beat the GOAT Serena?'
"If it's not me, I'm very okay with that," smiled the 33-year-old.
And asked if she genuinely felt Joint could prevail in their first-round clash, Tomljanovic responded: "I do, because Maya's quality is very high, even if you know the last couple months have been tough with her coming back from her back injury.
"I'm a big believer in things can really turn in a slam. Last year, she came to both slams after winning a title, and lost first round.
"Sometimes, it's just about timing. As long as she's mentally fresh, positive and believes in herself, even if last few months were tough, I think she'll be okay."
Joint was buoyed by Tomljanovic's 'pep talk' in which the former quarter-finalist told her she can beat anyone.
"I saw her this morning - she didn't ask me anything," laughed Tomljanovic, when asked if Joint would tap her brains about how to beat Serena.
"Well, that's Maya for you! I wasn't surprised, but I also think that it shows in a way she doesn't need help.
"Maya's quite introverted, but the more time you spend with her, she's very quirky, she's funny. She's very professional, she likes to stay in her bubble with her team, and you don't really get much from her."
Tomljanovic's advice? "It's really just for her not to overthink it, treat it as a regular match, but don't forget to also be aware of how cool the moment is -- if you're able to."
But the 64 million dollar question is how mum-of-two Williams will cope after so long away.
"I don't know. I really don't know," said Tomljanovic, breaking into a laugh. "A few of my friends practised with her, and they're all like 'she's playing great', so I'm just really excited to see it, because it's pretty impressive. Like you'd never see me out here at 44!
"She's in such great shape, and I don't buy this whole thing about she's only here to enjoy it; I think she's here to win. You never lose that champion mentality, so just her coming into the draw means she thinks she can win.
"She don't understand the numbers -- she's the greatest ever."
