A tale of two contrasting knockout teams

Mahela Jayawardene has the stalling semi-final knock that became a Kingston mauling in 2007. Kumar Sangakkara has the nifty World T20 final fifty. Lasith Malinga and Nuwan Kulasekara have their many tandem successes; trying batsmen with the new ball, tying them down with the old. Angelo Mathews, Lahiru Thirimanne, Tillakaratne Dilshan, Rangana Herath, Thisara Perera - they've all had star turns on big occasions. All can recall shots or balls or catches when nerves were held, opponents cornered, and matches turned.

"It's like a bank account," Jayawardene said of the moments that have clinched Sri Lanka knockout games. "All those good performances, you've deposited. As a group, and as individuals we can always reflect back and know that there's some things that you've achieved already. We think: 'This is what I've done in those situations, mentally and physically.'"

The knockouts is when Sri Lanka's cricket has taken taut, menacing shape in the past two World Cups, in which they have played more sudden-death matches than any other side. In between, there have been two gallops to World T20 finals. So the belief at training is palpable. Some players have been away from home since mid-December, but they are not pining for Sri Lanka just yet. "We've got two more weeks here," they say, "We're just focused on that."

All through this World Cup, Sri Lanka have eschewed talk of dominating the competition and instead focused on "peaking". Now that they are at the pointy end, they will reflect on the times they have collectively risen before.

They might recall flying to the Caribbean unfancied in 2007, before losing to South Africa and only scraping past against England. They would scorch past New Zealand to that final. Adam Gilchrist and a great Australia team would have to summon something special to shoot them down.

Sri Lanka may remember losing to Pakistan at home, in 2011, before heating up for a clobbering of England. So complete was their control over that chase of 230, Dilshan accidentally hit a four in the closing stages and apologised to his partner, who was running down a hundred. They would blow by New Zealand en route to the Wankhede again. Speckled through each recent marquee tournament are wins grasped from thin air, roaring fires summoned from embers from campaigns gone by.

South Africa, their opponents, are a study in contrast. They have all the form, but little of the nerves or the know-how. It has been said that big-match pressure puts South African minds in a muddle, but so many tournaments has it been without a single knockout victory now, even the muddles have become tangled in a heap on their own. Their grand inconsistency has been dealt with inconsistently. Graeme Smith used to bristle when the word "chokers" was put to him in a question. AB de Villiers has confronted the tag head on, even sometimes applying the term when his team had simply been outplayed, instead of outwitted.

Just in this tournament, while Sri Lanka have casually cast aside losses to two of the tournament favourites, essentially taking the view: "We just need to take care to get to the quarters, who we get is irrelevant," South Africa have appeared particularly hurt at their two defeats.

"I just want to sit in my room and feel sad," de Villiers said after the 130-run loss to India. He suggested his team may "not be as good as we think we are" and were "not prepared to fight it out", after the match against Pakistan. Then, not a week after having "nothing good to say about the team," de Villiers delivered as high-flying a self-appraisal as has been heard all World Cup long. "I 100% believe we are the best team in the tournament here," he said.

The thing is, he could well be right. At the very least, they should outgun Sri Lanka. De Villiers has not scored as many runs as Kumar Sangakkara, but he is unarguably more dynamic. Hashim Amla hit two hundreds and averaged 86 in the most recent series between these teams, which South Africa comfortably won. In Morne Morkel, Kyle Abbott and Vernon Philander, Dale Steyn has pace support that often daunts opposition batsmen. Lasith Malinga decidedly does not. Even in spin - that great pride of Sri Lanka - South Africa have appeared more polished in this tournament. Imran Tahir's 11 scalps have come at 23.36, far cheaper than Rangana Herath's wickets. If his finger doesn't heal, Herath may not even play at all.

Reason suggests South Africa should coast into the semi-finals. They are fitter and faster in addition to being so skilled. But they are up against opponents who give no heed to reason. Sri Lanka have been a side that sparks suddenly and emphatically around a spell, or a run out, or a cameo.

The Sydney quarter-final will not be the most-watched, nor does it feature the tournament's new favourite teams. But it is not short on intrigue, because on Wednesday evening, one team will seek to ride high on their emotion, while another strives to keep a grip on theirs.