They're tricky things, those key moments.
They come without warning and are decided by a choice, a reflex or a moment of sheer brilliance. They turn on calmness of mind as much as the execution of skill, and in must-win matches, they arrive with the burden of intense expectation and pressure.
The hackneyed adage in cricket is that South Africa lose key moments when their World Cup campaigns are on the line. You know the word, they know the word. It hovers around South Africa's throat until it ultimately cho… - sorry, my bad - until it ultimately throttles them.
South Africa have scrapped their way through to the semi-finals undefeated. They have not been convincing, they haven't produced anything approaching a complete performance, and yet they sit atop Group 2 in the Super Eight.
Needing to defeat West Indies in order to clinch a place in the tournament's knockout phase, an early key moment turned South Africa's way. Marco Jansen had removed Shai Hope in the first over, but a one-two punch would knock the wind out of West Indies' powerplay sails.
Suspecting the pitch was ripe for turn, Aiden Markram brought himself on to bowl, something he is often reluctant to do. It turned out to be an inspired decision, netting the wicket of Nicholas Pooran, who went on the attack only to hole out to long-on. Buoyed by success, Markram bowled his four overs in a single spell as part of a spinning onslaught; South Africa's quicks only bowled three overs in the first half of the innings.
"I think strategically he's been excellent," Rob Walter, South Africa's head coach, said after the match. "Tonight, there was some really smart captaincy and strategic plays that we know can go either way in T20 cricket. We had a good idea that the wicket was going to turn, and we knew if it did turn, what the match-ups would look like.
"The match-ups worked pretty well for us, and I'm just stoked that he actually backed himself to bowl four overs. I'm pretty much begging him every week to bowl more. He really did it today."
A pattern was repeated. Each time West Indies approached a crucial juncture of the match that could propel them in front, South Africa dragged them back. The introduction of Tabraiz Shamsi into the attack in the tenth over was critical. It wasn't just that he took three wickets, but it was also the way he responded to each attempt to take him down, absorbing the blows before counter-punching.
"Fortunately, I've been able to play CPL for the last five or six years," Shamsi said. "And one thing you know, with the West Indian boys, you don't have to guess what their intent is going to be. It helps you formulate a plan or expect what you're going to be coming up against, and then it's about trying to utilise the different variations you have.
"Everything sort of goes into slow motion with the outcome in the middle. It's just about doing the job for the team, and at times, the captain will ask me to strike - or at times he's asking to bowl it tight, so it's about trying to do that as best as I could."
The key fielding moment belonged to Anrich Nortje, just as Andre Russell threatened a trademark explosion. Russell had belted Nortje for consecutive sixes, but in the following over, he chanced the quick bowler's arm at short third, and the direct hit stalled West Indies' momentum.
In the rain-affected chase, South Africa went hard too early on a pitch that still had its demons, and lost their first three wickets early as a result; they were still on top, but the pendulum was deciding which way to swing.
Enter Heinrich Klaasen in the pivotal seventh over. A mighty mow of Gudakesh Movie down the ground for six was followed by three boundaries in a 20-run blitz.
"Chasing a score like that, normally it just takes one over that you can change the game [in], and make life a little bit easier for yourself," Klaasen said. "I've played with Motie before, and I know that he misses a little bit full. He's not a bowler that really misses short. I just decided anything full is going, hopefully, rooftops. That was the idea, and luckily, the first ball went nice and full.
"That was what my mind suggested, just taking on the first one. Anything full was going for six. That was the first over that I really wanted to go at, to put at least one of their spinners under pressure. And it just takes one over on a score like that to get it nicely under a run a ball, and then all the pressure's off. And then we made life difficult for ourselves once again."
South Africa kept stumbling, losing further wickets and entering the final over needing five for victory before Jansen hammered the winning six. If West Indies had pulled off a remarkable victory, this South Africa side would have worn the dreaded tag that screams of intergenerational trauma.
"Choke is losing a game we should have won, or being in a position of strength and then losing it," Walter said. "We said if we can't get over the line tonight, there would be commentary that that was a choke, and to be fair, it would have been because we just didn't make a decision under pressure.
"But there were enough good decisions made under pressure. We continue to work on it to play the pressurised moments a little bit better. We don't answer for the people who came before us. That was their journey. For us, it's about running our own race, and we've pretty much done that this campaign. It would have been a bitter pill to swallow losing only one game and not making a semi-final having won six in a row. We don't have to think about that now, fortunately."
There will be more key moments in the next game, and possibly, the game after that too. But Shamsi believes South Africa are now embracing life on the tipping point.
"The amazing thing is that this new Proteas team always seems to get over the line," Shamsi said. "We've been put under huge pressure basically in every single game that we've played. And the boys have managed to find a way to win no matter what the situation is, no matter how close the game. So that's really easy for us to do. In a funny way, we're looking forward to it."