What are the chances of an unbeaten 39 being among a frontline batsman's most important ODI knocks? Especially for a player who has an epochal 171 not out in the format against her name? It is, for very good reasons. And it could assume even bigger proportions. Read on.

Harmanpreet Kaur's big-match temperament is common knowledge. And there's no denying that her 171 against Australia in the 2017 World Cup semi-final has been one the most remarkable innings in not only her decade-long, 197-match international career, but also in women's cricket history.

For Harmanpreet, as with anyone that watched that paradigm-shifting innings - at least in the context of Indian cricket - there is still a tinge of disbelief. "Every time I watch the highlights, I wonder, 'main aise kaise maarne lagi (how did I start hitting like that)!'," she said in an interview to Star Sports in the lead-up to the T20I series against South Africa in Surat, which India won 3-1 last week under her captaincy.

That interview was first aired almost three weeks ago. Since then, she has played her first ODI on home soil in over 18 months, having sat out the previous home series, in February, with an injury that kept her out of India's ODI XI for the first time since February 2010.

It's a series that had kicked off with a first-ball wicket for Goswami and had been set up for closing out with a top-score of 66 on Friday from Raj. And Harmanpreet, the next most experienced player in the side, duly responded, her innings one that could set off the remaking of Harmanpreet, the ODI batsman

More recently, on Friday, she featured in India's highest successful ODI chase (248), the winning run taking her to an unbeaten 27-ball 39, and India to an unassailable 2-0 lead in the three-match series, rounding off India's fifth consecutive series win in the format.

Harmanpreet's 39 came off the back of a run during which she had been India's top-scorer twice in four completed matches in the T20I series in Surat. During that streak, she also became the second Indian woman - and eighth overall - to complete 2000 international runs in the shortest format and also became the first Indian - male or female - to play 100 T20Is.

Along with those impressive numbers came a commemorative rap by her much younger team-mates 'Lil J' [Jemimah Rodrigues] and 'Big Harry' [Harleen Deol].

The viral tribute to #HarmanpreetThor, penned in Hindi and performed by Deol and Rodrigues, valorises - somewhat comically - Harmanpreet's power hitting. In the closing moments of the 31-second video, though, appears a touching note that fuses - if unwittingly - the hurt of a dream deferred with unbridled optimism. Poora karna sapna hain, World Cup ab toh apna hain (We must fulfil the dream, the World Cup will be ours this time)," croons vocalist Deol.

Many a time, at India's moments of reckoning - at home and away, in bilateral and multi-nation series, at continental and world tournaments - Harmanpreet has shaken off a run off poor form, or injuries, and metamorphosed into the deliverer. Almost of the otherworldly kind, unstoppable in her destructive avatar, unflinching in her intent to rip the ball - and the bowler's morale - to its last shred. Her mantra: scratchy at first, and then go bish-bash-bosh until the changeover from Harmanpreet to Hammerpreet is achieved, the tone of India's performance on the day decided.

But the fulfilment of the World Cup dream continues to elude Harmanpreet and, more importantly, India, and the two pillars on whom stand much of the edifice of Indian women's cricket: Mithali Raj and Jhulan Goswami.

The two veterans had been absent from India's line-up during their previous highest successful chase (245), in Colombo in 2017, also against South Africa. Harmanpreet, who anchored India's innings with an unbeaten run-a-ball 41 then, had struck the winning runs on that occasion too. With India needing nine off the final over, Harmanpreet struck a six off the penultimate ball and then closed out the chase with two runs in a final-ball finish.

That was Harmanpreet's first 30-plus knock in eight ODI innings; the 27-ball 39 on Friday in Vadodara is her only 30-plus knock in her last ten innings in the format. A forgettable tour of New Zealand in January-February had Harmanpreet making an unconvincing 24 in her only ODI innings on the tour, and there hasn't been an opportunity since.

So, when she walked out to bat on Friday, with both set batsmen Raj and Punam Raut having fallen in the space of four deliveries, Harmanpreet had her work cut out. India needed 51 off 59, and the 50-over career of India's most-feared T20I batsman a shot in the arm.

It's a series that had kicked off with a first-ball wicket for Goswami and had been set up for closing out with a top-score of 66 on Friday from Raj. And Harmanpreet, the next most experienced player in the side, duly responded, her innings one that could set off the remaking of Harmanpreet, the ODI batsman.

Since that innings in the 2017 World Cup semi-final, Harmanpreet has made 12 30-plus scores in 29 T20I innings for her 781 runs at an average of 35.50, including her first ton in the format during the 2018 World T20. In ODIs, though, save for her 51 in the World Cup final, and later an unbeaten 55 against South Africa and a run-a-ball 21 against England, both in 2018, she has had little consistency between the 171 and the 39.

Starkly different as those two scores are, they re-establish Harmanpreet's credentials as a match-winner in ODIs. The big-game temperament defines Harmanpreet. But these knocks - even if the stakes are low (the series isn't part of the Women's Championship) - do play as vital a part in feeding the bullish self-confidence of a batsman who is known to veer between the outstanding and the mediocre.

That unbeaten 41 was a precursor to that 171 not out. Does the unbeaten 39 promise something big too? We'll see. Come the World Cups in 2020 and 2021, Harmanpreet will have her reputation as a big-match player - and that Lil J-Big Harry number - to live up to.

Annesha Ghosh is a sub-editor at ESPNcricinfo