An 18-year-old world champion
Matthews, all of 18, says she has never played in front of more than 200 people at home in Barbados. On the biggest stage in women's cricket, she was up against a side looking for their fourth successive world title. This time, though, she had the support of nearly 20,000 fans at Eden Gardens in Kolkata. Did it make her nervous? Not by the evidence of her whirlwind half-century, her first in T20 internationals.
Opening the innings, she chased down the target of 149 with 66 from 45 balls, popping Megan Schutt over the fence and Ellyse Perry back over her head early in the innings.
When the tournament started, Matthews was still 17 and legally not allowed to buy alcohol. It ended with her 18 and covered in champagne. The joyous leap into Carlos Brathwaite's arms and the celebration with the West Indies' men's team that followed touched Caribbean and neutral fans alike.
The first three overs West Indies faced fetched only nine runs. In the fourth, Matthews peppered the leg-side boundary for two fours off Rene Farrell. Those strokes were high-quality, but it was the sixes that followed in the next two overs that announced Matthews' intent. Schutt, a bowler experienced in delivering under pressure, sent down an inswinger on middle and leg. Matthews skipped down and smashed it over the midwicket boundary. Then she hit Ellyse Perry, one of the fastest bowlers in modern-day women's cricket, back into the stands. Australia huddled together for a chat. The teenager had lifted the run rate from three to more than seven an over, and was proving to be a headache for the three-time world champions. Another title suddenly looked less likely.
45 The highest score in a Women's World T20 final - by Jess Cameron for Australia against England in Colombo in 2012 - before Matthews broke the record. That innings had helped Australia prevail by three runs. Back then Matthews was trying her hand at athletics in school, confused about whether to take up cricket. Four years on, she scored the first half-century in a Women's World T20 final, the highest score by a West Indies woman in any World T20 game.
What they said
"A lot of people take so long to get something like that in their lifetime. That I could be part of that at such a young age really means a lot to me." - Hayley Matthews
"We saw bits and pieces of her, and she's very talented. She had a good series against us in Australia a couple of years ago, and played well for the Hobart Hurricanes. It wasn't a surprise. We didn't want her to do it today, but she played exceptionally well and was pretty hard to stop." - Meg Lanning
The closest contenders
Tammy Beaumont, 168 not out v Pakistan, third ODI, Taunton
Beaumont became the first English female cricketer to score back-to-back ODI hundreds, and her 168 was the fourth-highest women's one-day score.
Harmanpreet Kaur, 46 v Australia, first T20I, Adelaide
Harmanpreet helped India pull off their highest successful chase in T20Is and take a series lead, which they then converted into a first ever series win against Australia in any format.
Shashank Kishore is a senior sub-editor at ESPNcricinfo