If there was anything noticeably different to the Smriti Mandhana on Saturday in Derby from the Mandhana who had first toured England in 2014, it was only the contact lenses.

In the brief history of televised women's matches, it was the first time that Mandhana had come in to bat without her glasses. Even though their absence may have robbed her of some of the trademark sincerity that her facial expression under the helmet has come to bear, the glint in her eyes never shone more fiercely than it did at India's 2017 Women's World Cup opener against England, as she smashed a match-winning 72-ball 90 to set up India's 35-run win.

It was not only Mandhana's World Cup debut but also her official comeback innings after a five-month injury layoff. A ruptured anterior cruciate ligament sustained during the second edition of the WBBL on January 15 had ended her WBBL stint prematurely. However, by her own admission, what was more disappointing was to miss out on the Women's World Cup Qualifier in February and the Quadrangular series victory in South Africa last month.

With the injury having almost jeopardized her participation in the World Cup, Mandhana made a point in her Player-of-the-Match acceptance speech to reiterate her gratefulness to her coach, Anant Tambwekar, and to the medical team at the National Cricket Academy in Bangalore. She had spent the greater part of the last five months at the NCA, recovering under physiotherapist Yogesh Parmar and trainers Anand Date and Rajinikanth.

"The last four and a half months have been tough for me and I am really thankful to the NCA, Anant sir, Yogesh sir, whoever made it possible for me to play this match," Mandhana said. "Those were really tough four and a half, five months, but if we do well at the World Cup, it's going to pay off."

Stumbling into Mandhana during her rehabilitation at the NCA in late March would be the then India Women's head coach Purnima Rau, who was attending a coaches' training programme at the academy, under the Representative (Level 2) courses jointly organised by the BCCI and Cricket Australia. Upon finding Mandhana in the training arena, Rau would watch her go through the brisk-walking and running sessions as she tried to regain fitness step by step.

"There was a steely resolve in her eyes," Rau recounts. "Though she was going through the rehab, that look was always there. It was something very powerful, you know, that hunger to break through the bleak phase… you could see it."

Rau's words resonated well with the single-minded irreverence that Mandhana, the No. 38-ranked batsman in Women's ODIs dished out to the No. 4-ranked bowler, Katherine Brunt. The first ball Mandhana faced, a short ball angled into her hips, was swatted for a one-bounce four behind square.

Mandhana played a near carbon-copy pull off Brunt to the midwicket boundary on the second ball of the fourth over before three caressed back-foot drives to the off-side rope ended a 16-run frame. It was a reprise of the back-foot dominance Mandhana displayed against the Australian medium pace duo of Ellyse Perry and Holly Ferling during her maiden ODI century in Hobart last year.

The treatment Mandhana meted out to Natalie Sciver was no different. Replacing Brunt to bowl the sixth over, Sciver repeated the same mistake as Brunt by going short with her first ball to Mandhana, who rocked onto the back foot to greet her with a pulled six over midwicket, and a smile down the pitch. Three balls later, Mandhana was merciless to a fractionally short delivery, scything it over the leg side for one more boundary.

Mandhana would consign the other medium-pacers - England vice-captain Anya Shrubsole and Jenny Gunn - to a similar fate. The shot that Mandhana played to bring up a 45-ball half-century, a lofted drive off Gunn over extra cover, was all grace and little menace.

In an interview to ESPNcricinfo ahead of the World Cup, India captain Mithali Raj had said Mandhana's reintegration into the top order may not be easy, owing to the consistency shown at the top by fellow youngsters Deepti Sharma and Mona Meshram.

However, given that Mandhana had "scored a lot of runs in England in 2014", Raj hoped the now 20-year-old "will be among the runs in the World Cup". It is this faith in Mandhana's experience and efficacy in overseas conditions that may have led Raj to pick her in the tournament opener, alongside both Deepti and Meshram.

When asked about Mandhana finding fluency on her comeback innings, Shantha Rangaswamy, the former chairperson of the BCCI women's selection committee, did not express much incredulity.

"If you assess the caliber of this girl, this knock doesn't come as a surprise," Rangaswamy said. "She is one of the most focused youngsters in the side, and has been so all through; else she wouldn't have been able to rise through the ranks so easily. She has worked hard to get past that injury - both mentally and physically."

Rau echoed Rangaswamy in her assessment that there is a depth in Mandhana's head-space that she can plumb at will. It is almost as if Mandhana can summon something "very powerful, very mystical" from the recesses of her mind to negate any physical pain, any sort of defeat.

"As a coach, one of the first things I had noticed in Smriti is her aggression," Rau said. "It is not the usual full-of-animation kind of aggression, but a quiet and latent one. When she puts her mind to something, she'll want to give it all, come what may. No matter what the situation - low, high, pain, no pain - under all circumstances, she'll give her 100%. She may stutter, she may fall, but she'll keep going against all odds."

Rau had seen Mandhana from close quarters when she had injured her shoulder in the third T20I against Australia at the SCG last year, prior to the three-match ODI series. Mandhana was forced to sit out the first ODI in Canberra, but took less than a week to recover and made it back into the starting XI for that second ODI in Hobart where she notched her maiden ODI century.

"The resilience she showed in that Hobart hundred is not something you get to see every day, or from everyone," Rau said. "Her ability to zone-out pain is incredible. [It] speaks volumes about her character and not just her talent."

In that ODI in Hobart, she had forged a 150-run second-wicket stand with Raj, plundering 11 fours during her 109-ball 102. Against England on Saturday, she put on 144 for the opening wicket with Punam Raut, bashing as many fours and two sixes during her 72-ball knock.

Outside of missing a ton by just 10 runs, the only other blemish for Mandhana on the day came when she limped off the field in the 16th over of England's innings with a left leg injury. Mandhana had put in a sliding stop on the square leg boundary in an effort to prevent a four by Sciver and it initially appeared that she may have reinjured the same left knee that kept her out for most of the year. Mandhana said afterward it was not the knee but rather a slight hamstring strain and was hopeful of being fit for India's next match on Thursday against West Indies.

Perhaps the hunger for making it back to the XI that kept her going through the layoff spurred her on to a comeback of this kind. That it was in England, where an 18-year-old Mandhana had announced herself on the world stage with a half-century on Test debut plus a fifty in her first ODI on foreign soil, was particularly fitting.

"There is something very deep about this girl, something very strong," Rau says. "There's a measure of quality tinged to her batting and her career… a degree of class. Wherever she finishes, at the end of the road, that quality tinge will be there."

Annesha Ghosh is a sub-editor at ESPNcricinfo