On Tuesday, Dale Steyn left the World Cup without bowling a ball. It was unfortunate to say the least, irrespective of your loyalties. Only because the World Cup is the platform to witness the best, and their battles against the best. That, however, hasn't left the World Cup bereft of top-of-the-line fast men. Leading that contingent are Kagiso Rabada and Jasprit Bumrah, two young pacers, who have the skills and the brains to intimidate batsmen. If you need proof of that, just revisit their opening spells on Wednesday.

Let's start with Rabada, it was the more eventful - though perhaps not as impactful - as Bumrah's.

Rabada shakes and stirs the Indian top order

On Tuesday afternoon, Rabada playfully engaged in a roaring contest with teammate Chris Morris. Both men let their emotions out by roaring as loudly as possible. For a tiny moment, Rabada's face, glistening with sweat, revealed a sense of joy, a sense of unbridled and uninhibited excitement that is at the core of his craft.

Emotions, Rabada told The Cricket Monthly recently, can transform a bowler into a dangerous beast, equipping his bow with that extra, intangible string, that can pierce the batsmen's mind and defence.

Today, Rabada must have been angry even before he lined up to deliver the first ball. South Africa's batsmen had disappointed for the third match in succession - they scored 227 for 9. The absence of Steyn and Lungi Ngidi (hamstring injury) meant Rabada had more on his plate than he might have otherwise.

From the crowd's point of view, the match-up the fans were looking forward to was Rabada v Virat Kohli. The past contests had already witnessed enough needle between them. Today's match-up became a notch bigger because of Rabada's remarks concerning Kohli's unapologetic, intense attitude on the field, which he said had left him to wonder whether the Indian captain was "immature". Kohli responded too.

Rabada warmed up for Kohli with a beauty of a first over, by the end of which he should have got both Shikhar Dhawan and Rohit Sharma out nicking off, both pushed back into uncomfortable positions when playing their shots.

By the end of the over, Rabada was roaring. Far from being one of delight, it expressed disgust and disappointment at the close-in fielders failing to get their hands under the top edges. Rabada would return to up the ante in terms of speed, catching Rohit on the hop more than once. Rohit was attempting to connect as far as possible on the front foot with Rabada pitching on a length. However, he was beaten both for pace and the bounce Rabada generated off short-of-length and length areas form the Pavilion End. Rabada finished the over with a yorker-length delivery that dipped in to Dhawan, and broke the toe end of his bat. Rabada could only stare at the flying chip of wood.

Rabada was now his element. The batsmen were shaken and stirred. First ball of his third over, he angled one off the seam, pitching it on length. It was the kind of delivery James Anderson had troubled the Indian batsmen with in the Test series last year, beating the outside edge several times. Rabada did not beat the edge, he caught it. Dhawan walked back.

The moment of the World Cup arrived, as Kohli walked each of the 45 steps down to the pitch from the dressing room. Kohli quickly took guard. Flicked the bat. Bent his head, raised it, waited. Rabada ran in and banged in a 91mph bouncer. Kohli ducked his first ball of the World Cup. A roar went around the ground. The next ball was a full toss. Kohli's bat face turned inwards on impact.

Kohli wanted to get off strike. Rabada suffocated him with speed and accuracy. There were no stares or words yet. The ball was talking though. Quietly.

But Rohit had had enough. When Rabada went slightly wide off the crease and banged in a short-pitched delivery into the ribs, Rohit went with the flow, pirouetted on his right leg and pulled a delectable six, sending the sell-out crowd into frenzy. As beautiful as the stroke was, it was also an impulsive reaction, a release. From the vice-like Rabada grip.

Rabada might not have picked another wicket in his unrelenting first spell of five overs, but he had set up the contest for South Africa. And although it was Andile Phehlukwayo who was the next to celebrate when he forced an edge off Kohli, Rabada had the satisfaction of not letting the world's best batsman start the tournament on a big note.

The intensity never dropped, and Rabada returned for more spells, and eventually claimed KL Rahul with a slower delivery. He did not roar, but did not let out a smile either. And when David Miller dropped a dolly off Rohit with the batsman on 111 and the target just 31 runs away, none of the South Africans wanted to look at the bowler.

He had done all he could. His mates let him down.

Bumrah makes the batsmen hop, skip and jump

When the world's best bowler runs in, there is a sense of anticipation. Bumrah announced himself pretty quickly in the World Cup, building the pressure straight from the first ball. His first was on a length, straight at Quinton de Kock's middle stump. The second was short of a length and moved away. The third left the South African left-hander as it shaped away. Off the penultimate delivery, Bumrah pushed the length a wee bit fuller, pitched it on a middle stump line and then angled it away. de Kock had to play. He did. And was beaten. De Kock often looks unhappy. Now, he was seriously uncomfortable.

Bumrah had warmed up. He came up with a jaffa, repeating the same ball, but slightly quicker, beating the bat, and MS Dhoni, who had moved to his left, failed to collect neatly.

Hashim Amla would have known one thing as he faced his first ball against Bumrah - his stumps would be attacked and he would need to play. Bumrah pitched on off stump, length again, moving it away. Amla, as if under a spell, just followed the ball and edged it to second slip.

The challenge against Bumrah is he does not give the batsman too many loose balls. In his first two overs, batsmen were not in control nine times. In his third over, Bumrah altered his length and pitched fuller, luring de Kock to go for the drive. He went for the release shot, like Rohit would against Rabada later. However, de Kock was not in control, and the thick outside edge flew straight to Kohli in the slips. Joy for Bumrah.

"You know it's one thing to see a bowler bowl, and then when you catch the ball, you understand the heaviness of the ball and the pace," Kohli told Star Sports after the game. "And I caught that ball, I promise you, for the next 15 minutes, my hands were buzzing. And I told him (Bumrah), you know, that I can feel the pain in my hands. That's how quickly he's bowling."

Bumrah's first ball to Faf du Plessis was bowled at 144 kph, pitched on length and was angled into the pads. The South Africa captain attempted to play on the front foot, but the speed forced an inside edge. The crowed let out a huge "ooh". Two deliveries later, Bumrah shaped one away. This time, du Plessis read it and played with soft hands.

As he said between the two innings to the host broadcaster, Bumrah was just keeping things simple, making use of the fresh Kookaburra ball on a fresh pitch, landing on a straight seam and letting the ball do the talking.

Just like Rabada would later.

On Tuesday evening, heading out for dinner, Steyn was far from remorseful about heading back home. "The world's not come to an end," Steyn told this correspondent with a twinkle in his eye.

He is right. His legacy is strong in the hands of Rabada and Bumrah. And, no, don't ask whose spell was better.