There is someone playing in the WBBL finals this weekend who has been player of the match in a World T20 final and a World Cup final. Someone who has reached the highest level of two sports and still plays both concurrently at the domestic level.

The Melbourne Renegades captain Jess Duffin is one of the form players of the tournament making 500 runs at an average of 71.72 with five half-centuries including three in a row leading into the finals weekend. But Duffin can't quite work out where her form has come from.

"It's a good question," Duffin told ESPNcricinfo. "I haven't really thought about it too much to be honest. I went into the season the same way I have every other year but as I explained to other people in the past, it's T20 cricket, anything can happen, it's a bit up and down."

Duffin's sporting resume is quite remarkable. In an era where female cricketers are becoming national icons, Duffin appears, at times, to be persona non grata. In part, it is because her international cricket career came to a sudden halt four years ago and it came under a different name.

Jess Cameron, as she was known prior to getting married, had a stellar international career for Australia. She has played in three World T20 triumphs for Australia and was player of the match in the 2012 final against England scoring 45 off 34 balls.

Her ODI record was even better. She made 75 from 76 balls in the 2013 final against West Indies.

But she hasn't played for Australia since 2015, stepping away from international level by choice at just 26. While still playing domestic cricket in the WBBL, she has instead been playing Australian Rules Football, starring in the AFLW for North Melbourne, earning a place in the All Australian team, the league's team of the season, earlier this year.

Duffin has made the WBBL team of the year this season as captain after leading the Renegades to another semi-final. Of the eight players to have made 400 runs or more, she has the highest strike-rate, 140.05, by some margin and is the only player who doesn't currently play international cricket.

After years of worrying about her own form and her own performance she has discovered that the captaincy, which was thrust upon her due to Amy Satterthwaite's pregnancy, might be the secret to success.

"In the past couple of years I probably haven't really backed myself in terms of trying to get the team over the line," Duffin said. "But this year with the captaincy…I don't get time to think about myself because I'm trying to help them in the situation we have in front of us. So it's probably been a good thing not focussing on myself too much.

"I think it's just more about understanding the game of T20 cricket. I haven't really had to think about it in the past because we've had other captains do all that sort of thinking for us. So I've had to do a lot of work behind the scenes in terms of looking at footage and watching other people play."

Studying vision of opposition to gain a competitive advantage has helped Duffin guide her young middle order through some tricky chases. She admitted it was something she didn't do enough of in her six-year international career.

"We used to do it as a group when we were sitting in batting and bowling meetings and stuff like that but I didn't go the extra mile and have a look myself," she said. "So that's probably one area I've probably been a bit better at, just in terms of my research. But I think that's because I'm captain and I kind of need to know what these players are doing. I've tended to watch a bit more than normal."

Duffin's form has now raised questions about a recall to the Australia side for the T20 World Cup next February. But her availability is complicated. She declined the opportunity to play for Australia A against India A in an upcoming series and the 2020 AFLW season clashes with the T20 World Cup in March.

Complicating matters further, Duffin doesn't even know what she would like to do.

"Not really," Duffin said. "I haven't really thought about it to be honest. I know there's been a lot of talk about my selection and stuff and I haven't had any contact with the selectors at all and you look at that [Australian] line-up and think 'well, where am I sitting?'. There's some really good players in there at the moment and my sole focus this weekend is to make sure we come out on top on Sunday."

For now, Australia, North Melbourne, her personal training work, her husband and her dogs all run a distant second to leading the Renegades to victory and atoning for last year's heartbreaking semi-final loss against the Sydney Sixers in a super over.

The Renegades have been shorn of their two England stars Danni Wyatt and Tammy Beaumont, but they have gained Chamari Atapattu who made a century against Australia in October in Brisbane.

"Hopefully she can do what she did the Australians a couple of months ago and dominate on Saturday," Duffin said. "With the ball, we've obviously got Lea Tahuhu upfront and Molly Strano has been doing a really good job for us throughout the middle so we can throw the ball to anyone at any time and anyone can step up.

"We do match up well against [the Brisbane Heat]. I think it's about going in with a pretty clear plan and obviously we know they like to score big so it's just trying to restrict that. They've got Beth Mooney and Jess Jonassen up the top who are in some really good form so it's just having the right plans for them and just obviously going out and executing."

The Heat will need their own plans for the unassuming Duffin, who has reminded everyone this year just how good she is.