After a heartbreak in a final-ball thriller in the 2017 ODI World Cup semi-final and a group-stage exit in the 2018 T20 World Cup, South Africa are faced with a moment of truth again. A team that for long has exuded promise on paper but come up short at vital phases, must now make the most of the "best chance" they've had in recent memory of winning a maiden T20 World Cup.

"We've said from the start that this is the best chance South Africa has ever had to win a World Cup," an emotionally charged Dane van Niekerk said on the eve of their semi-final against hosts and defending champions Australia.

"We've got the best team we've picked in a very long time. It's a semi-final; anything can happen. What happens on the day, we're going to focus on what we do well and forget about the records. It doesn't matter in a high pressure game like tomorrow. Hopefully, we can get one up on them for the first time in, I guess, forever."

South Africa will play in the semi-finals for just the second time in seven editions, on the back of topping Group B with three straight wins, including against last edition's runners-up England. In contrast, Australia have not had it straightforward in the tournament, losing to India and doing just enough to avert a disastrous defeat against Sri Lanka.

The odds might favour the visitors, but with uncertainty around the match-fitness of their star allrounder Marizanne Kapp, who is battling a respiratory tract infection, and given the pedigree of the opponents, van Niekerk is well aware that "babies" South Africa will need to put their best foot forward to qualify for the final at the MCG on Sunday.

"It will probably be up there with one of the toughest games we've had," van Niekerk said. "Australia have been in so many semi-finals and finals. We are babies compared to them when it comes to the experience.

"It's probably up there as one of the toughest games and one of the most competitive that we'll be part of, bar the England game. The England game was quite competitive and stressful. We're just excited to get out there - we just want to show the world what we're made of as a South African cricket team."

South Africa's standout performers in the league stage have come from both the bowling and batting departments. Opener Lizelle Lee clubbed a century against Thailand, young batter Laura Wolvaardt struck a fifty against Pakistan, Shabnim Ismail has often pegged the opposition back in their pursuit with her tight lines and pace, while spinner Nonkululeko Mlaba has also been penetrative with the new ball.

The onus of orchestrating Australia's undoing at the SCG rests, though, to a great extent on lesgpin-bowling allrounder van Niekerk and Kapp, given their familiarity with Australia and local conditions as members of the WBBL franchise, Sydney Sixers.

We don't want the heartache of 2017 again. It was very tough for a lot of the players and management, we're definitely going to do everything we can tomorrow to make sure we don't have that feeling again

"Mentally, it's a personal mindset shift," van Niekerk said. "We've spoken a lot about how the Big Bash and the Super Leagues have helped a lot, you start to play against and with the best players in the world and you stop doubting yourself as a cricketer.

"It's very easy to not be in the big three in the world and think that if you don't play for Australia or England that you're not good enough. But when you start playing with and against them, you see that your skill holds up really well against those big names. We've got record-breakers within our side as well, the Big Bash has helped with confidence as individuals.

"We have fond memories and love playing at the SCG, it's our home away from home. I have to stay true to South Africa but this is probably my second favourite ground in the world. It's given us a lot of good memories with the Sixers, we understand the deck better than people who haven't played here.

"We understand the ground and it helps in our favour. I thanked Cricket Australia and the Sixers - they helped us a lot with a lot of inside information bringing us over for the Big Bash."

All factors considered, the strongest driving force towards vying for nothing short of a win on Thursday, in van Niekerk's view, remained as much the prospect of a glorious future for South African cricket as the hurt of heartbreaks that mired their past.

"I think about 2014 - we were shell-shocked that we got into the semi-finals," said van Niekerk. "You go there wanting to do well in a tournament, but it's different to say you're going to come and win a World Cup. I don't think we quite understood then what it meant mentally, physically. We've been on tour 54 days already, it's not as if we've just come over here and are on a 20-day tour.

"We've played the most international cricket out of everyone, it just shows the preparation and learning how to go about it. That's helped us a lot in this World Cup. We don't want the heartache of 2017 again. It was very tough for a lot of the players and management, we're definitely going to do everything we can tomorrow to make sure we don't have that feeling again."

Annesha Ghosh is a sub-editor at ESPNcricinfo