South Africa captain Temba Bavuma won the toss and opted to bat first at Eden Gardens, where they quickly found themselves in all sorts of trouble at 24-4 inside the opening 12 overs.
Ultimately having managed a total of 212 all-out, thanks largely to David Miller's century, the bowling attack struggled to defend the modest total as the Aussies reached an eighth World Cup final.
Walter, however, insisted there was no choking this time.
"Yeah, I mean, I guess you need to define what a choke is. For me, a choke is losing a game that you're in a position to win," defended Walter.
"In this instance, we were behind the eight ball right from the word go and we actually fought our way back into the competition and put up a score that gave us a chance.
"And then, again, they got off to a flyer and we fought and we put ourselves back into the game – and, of course, we were 30 or 40 runs short.
"But still, having them seven down and a couple of things, balls bouncing just short, a little inside edge that could have been taken, you know.
"So, for me, there's nothing even remotely close to a choke that happened out there today. It's a serious contest between two good teams, number two and three in the tournament."
Reflecting on where things went wrong, the former Titans mentor admitted the early batting collapse under tough conditions in the opening stages of the match cost them a respectable and more defendable total of around 270.
"Yeah, it's obviously gutting to lose a semi-final. But beyond that, incredibly proud of the fight shown by the lads. The first 12 overs of batting this afternoon was a serious challenge," he noted.
"And, ultimately, I think that's what separated the game really – 24-4, even to come back from 24-4, the way Klaasie [Heinrich Klaasen] and David Miller batted together in that partnership.
"Unfortunately, Heinrich's just getting out when the momentum was really starting to turn in our favour, but then the way, again, Gerald [Coetzee] partnered with Dave [Miller] and the tail to get us to 213.
"Obviously short – I think 270 was the sort of total that we were speaking about, but even 250 would have proved to be a serious total there."