Northern Knights welcome Mitchell Santner back for the 20-over Super Smash after he seals an epic Test win for New Zealand against Pakistan at the Bay Oval. They throw him into the mix in the powerplay, but a certain Wellington Firebirds rookie right-hand opener switches his stance, turns into a left-hander, and monsters New Zealand's premier T20 spinner into the grass banks beyond midwicket at the Basin Reserve. It is arguably the shot of the Super Smash season. The opener treats New Zealand seamers with similar disdain, galloping out of the crease and going over the top like he is casually range-hitting net bowlers. Ask the likes of Matt Henry and Scott Kuggeleijn.

Finn Allen's chart-topping tally of 512 runs in 11 innings at an average of 56.88 and strike rate of 193.93 lights the Firebirds' run to the title. A day after winning the Super Smash, he is called into the New Zealand T20I squad as a standby player. A few weeks later, he is called into the Royal Challengers Bangalore squad as a replacement player for IPL 2021. A week after that, he gets a gig with Lancashire for the T20 Blast. He is just 13 T20s and 21 years old but there are already signs that Allen could be a white-ball star.

A day out of the Super Smash final, Allen said to ESPNcricinfo that he had no expectations of being picked in the IPL, but after Josh Philippe opted out of the upcoming season, RCB's director of cricket reached out to Allen.

"Hey Finn, Mike Hesson here. Give a message when you're free for a call," was the text, Allen says. After hearing the news of his maiden IPL deal with the Royal Challengers, where he will team up with the likes of Virat Kohli, AB de Villiers and Glenn Maxwell, Allen told reporters that he "nearly cried and genuinely didn't know how to react".

Such a rapid rise looked like a dream even as recently as the start of the 2020-21 New Zealand domestic season, when Allen was wondering whether he could fit into a robust Wellington set-up, having moved from Auckland in search of more game time. He made his senior debut for Auckland in 2017, but got only a further 21 matches across formats there over the next three years.

"It [the move to Wellington] came about after I spoke to the New Zealand Cricket Players' Association members [to] see if anyone else would be interested in having me," Allen says. "Wellington showed keen interest straightaway and I got a phone call from Glenn Pocknall [the head coach] the next day.

"I didn't think Wellington would be interested in me at all, given the number of good players they've got. I sort of thought: 'Wow! How am I going to fit into this side?' He called me and said he thought I was a good player and he was keen to have me at Wellington. I was pretty excited by that and within the next few days Glenn called again to give a ranking and I could see where I stood within the side. I took a bit of time to think, spoke to Auckland, and took the decision a few weeks later."

Just as Allen was getting used to living away from home and finding his way around a new team, he was concussed after being struck on the head while training during the four-day Plunket Shield season. He was sidelined for about five weeks and ended up missing the first four rounds of the 50-over Ford Trophy. He then eased himself back into action with scores of 30 and 6 from No. 4 against Auckland.

When Allen ran into his former team again, on Christmas Eve, in the Super Smash, he laid down the marker with a 23-ball 53 in his new role as an opener. It was the first of six half-centuries Allen would hit in the tournament, the highlight being the 16-ball one against the Central Stags. Only Kieran Noema-Barnett (14 balls) and Martin Guptill (15) have struck faster fifties in New Zealand's domestic T20 competition.

Allen puts his barnstorming Super Smash run down to an uncomplicated see-ball-hit-ball approach. "I guess I would say initially it was about having a plan," he says. "For me, it's quite simple and then sticking to it. Along with that, I made it a key focus of mine to emphasise watching the ball as hard as I can until the bat and trying to hit the ball hard. Probably the simplicity of it all is what got me going, I guess."

Allen also credits his off-season fitness training amid the coronavirus pandemic and unstinting support from Pocknall for his success. "The winter just was gone with Covid and everything, but I was lucky I had a gym at my home in Auckland. I did a lot of fitness work and running to progress that side of my game," he says. "Once I came to Wellington, they worked hard and are a very professional unit, and training was very tough - it helped push my game a little bit further.

"[Power-hitting] is an effect of being fitter and stronger. I also think the way the coaches have given me the confidence to play how I want to play - be free and express myself - really helped me. I'm someone who is a big confidence player - as most people are, but for me that backing really gets me going. I was told two or three days before the first game against Auckland that I was opening and I was kind of a little bit scared and nervous at first. I sort of thought, 'Oh my gosh! I don't think I'm good enough to open, I'm not up to that', but they really backed me to the hilt and told me that they felt that I was well suited for the role."

Roll back to that stunning switch-hit off Santner. Allen recalls that he had never practised the shot until the lead-up to the game against the Knights.

"I usually just use the pace of the bowler and it's always along the ground," Allen says. "Leading up to the game against Santner, I thought to myself - he's pretty hard to hit straight; you see a lot of dismissals straight down the wicket, and I thought: How can I have a different option to combat him?

"Switch-hit was one. I only practised it two or three days before the game and I was lucky to face a lot of left-arm spin in the nets. I think I spent one training session batting left-handed the whole time and just getting used to that movement. Fortunately, it came off in the game. I was pretty shocked when it came off the way it did!"

There was a bit of Kevin Pietersen in that shot, and perhaps there is a bit of Brendon McCullum when Allen dashes out to the quicks. Allen, whose father is from the UK, says that Pietersen's aggression has been a major influence.

"For me, Kevin Pietersen was always someone that I just loved to watch. I'm sure a lot of people are on the same boat, watching him take it to the opposition and how aggressive he was in his nature of play… That just really excited me and I always thought I want to be like that. Not necessarily look like him or play like him in that way, but just the same intent - the way he goes out there, puffs his chest out, and you know he's full of confidence and ready to sort of do damage. I suppose if I can mirror any form of that confidence and intent that he has, I'd absolutely love that."

Allen had a stint at Brondesbury in the Middlesex league between two Under-19 World Cups for New Zealand in 2016 and 2018, which he reckons prepared him for the rigours of top-flight cricket, particularly helping him get better against spin. It showed in the second of those World Cups, where he was New Zealand's highest scorer and fourth-highest overall.

"I guess it's all about playing more and more cricket at a higher level," Allen says. "My first World Cup, in Bangladesh, was pretty eye-opening. It was pretty cool to be part of it and I didn't expect to be in the side. The look on my face when my name was read out on the team sheet was probably excited and shocked. The second World Cup [at home] was one that I was more hopeful to make, and I had higher expectations of myself in terms of runs and getting close to winning the World Cup."

The sweep and reverse-sweep were productive shots for him in that second World Cup. Allen puts it down to how he practised it and working with coaches on it during his time in Middlesex. "And yeah, I suppose it's still working and I'm learning to play on different grounds. I went over [to England] with a Kiwi, Ben Sears, travelling with him was cool and it made things comfortable. The biggest learning was about myself and my game.

Allen will be back in the UK later this year, straight after his RCB stint. Before all of that, he is set to make his T20I debut against Bangladesh. It remains to be seen whether he can live up to the early hype in international cricket and big T20 leagues, but his clear sense of perspective will probably stand him in good stead as he tackles those challenges.

"I don't pay too much attention to [outside noise] at all. For me, it's about contributing to wins for my team and putting scores on the board, and fingers crossed, all that stuff will take care of itself," he says. "My parents obviously love to read the media and see what they're saying about me, but for me it's niggly to be caught up in it, and it can sort of take your focus away from things. Sometimes, it's not nice either. I try to stay away from that stuff and focus game by game."

Deivarayan Muthu is a sub-editor at ESPNcricinfo