Beau Webster barely had time to react. Marco Jansen ran in, pitched a good-length ball outside off stump and watched it climb sharply as it moved away off the surface. The batter, staying back to play through the off side, could only manage an edge that flew towards second slip. Aiden Markram flung himself across and pulled off a stunning catch to complete the dismissal. Jansen had his fifth, and Australia were in the doldrums at 84-7 in their first innings at Gqeberha.

There is something wonderful about watching a fast bowler in full flight. The long strides, the gathering momentum, the high arm and the ball thudding into the pitch all make for a compelling sight. Add a towering frame to that, and you expect bounce that can unsettle even the most accomplished batters. The possibility of swing only makes the prospect of facing such a bowler more daunting.

Few embody that spectacle quite like Marco Jansen. Since making his Test debut in December 2021, he has taken 102 wickets at 20.95 in 24 Tests, while scoring 822 runs lower down the order. At 6ft 8in, he is quite literally towering over the competition, recently sitting at the top of the ICC Test bowling and all-rounder rankings.

Jansen’s impact was evident recently against Australia, for which he was named Player of the Series. He claimed 13 wickets in six innings at 19.76, with his 5-33 at Gqeberha arguably the spell that turned around the contest. Operating with steep bounce and sharp seam movement, he helped dismiss Australia for just 99, and the team could never recover. His contribution was not limited to the ball, either. His lower-order batting provided South Africa with valuable runs on several occasions, adding to his importance as an all-rounder. But it is his bowling that has made him such a difficult proposition.

What makes Jansen such a threat with the ball?

His height is an obvious advantage. A higher release point changes the trajectory of the ball, but Jansen’s effectiveness is not simply a matter of being tall. His average release height of 2.21m is not the highest among the bowlers: Mohammad Irfan, for instance, averages 2.325m.

CricViz measured the height at which deliveries pitching between seven and eight metres from the stumps - around the good-length area - reached the batter. Jansen’s deliveries arrived at an average height of 0.97m, the second-highest among bowlers, behind Chris Tremlett (0.98m). He was ahead of Will O’Rourke (0.96m) and Blessing Muzarabani (0.96m).

Jansen does not need to push the ball short to make his height count. He can extract considerable bounce from a good length, forcing batters to decide whether to commit to the front foot or stay back. Neither response is particularly comfortable when the ball carries as much as it does off the pitch. But bounce is only one part of what makes Jansen difficult to face. How he varies his lengths, and the different problems he creates with each, is just as important.

Good-length deliveries account for 41.3 per cent of Jansen’s Test bowling, making it his most-used length. He has turned to it increasingly over time, with a corresponding decline in the proportion of full deliveries. His average speed, meanwhile, has remained remarkably consistent, ranging from 134.41 to 135.27 kmph across the years. Although the 2026 figures cover only three Tests, they point to a greater reliance on the good length rather than an attempt to extract more pace.

Batters have a fairly clear response to his fuller and shorter deliveries: playing more on the front foot, while the majority of his hard-length deliveries are played off the back foot. Against his good-length balls, however, the split is much closer, with 45 per cent on the front foot and 36 per cent on the back foot. That does not by itself prove indecision, but it shows batters cannot settle into one method. Go forward, and the ball can climb; stay back, and its extra carry can take it past the bat.

Jansen's good length has a false-shot rate of 18.8 per cent, lower than the 21.3 per cent against his hard length. So the good length does not necessarily produce the most mistimed shots. But batters have found it harder to find a response against the good-length ball, and neither playing it on front-foot nor a back-foot has been particularly straightforward.

And to his credit, Jansen is not reliant on the good length alone. He has taken 27 wickets with full deliveries, the same number as from good-length balls, though at a higher average - 25.86 compared with 20.76. Eleven of those full-ball dismissals have been bowled, with another two LBW. The fuller ball allows him to attack the stumps directly, a threat that complements the bounce he extracts from a good length. Batters looking to stay back against his deliveries cannot afford to neglect the possibility of a fuller ball.

He has also taken 21 wickets from back-of-a-length balls and another 11 from short deliveries, with all 32 dismissals coming through catches. His shorter deliveries make batters contend with the extra bounce, often forcing them to play away from their body or adjust to a ball rising towards them. Even a small misjudgment can result in a mistimed shot or an edge carrying to a fielder.

The Australia series offered a glimpse of just how many ways Jansen could trouble a batter. At Durban, he repeatedly tested Nathan Lyon with short deliveries before switching to a yorker that trapped him leg-before. Lyon had been pushed back by the threat of bounce, but Jansen changed the length, catching him in his crease when he was expecting another short ball.

That threat of bounce was particularly evident in his contests with Matt Renshaw, who fell to Jansen's bouncers twice during the series. At Gqeberha, one climbed sharply and took the edge as Renshaw tried to defend, while in Cape Town, he misjudged the bounce of a shorter delivery outside off while attempting a ramp over the wicketkeeper.

Jansen could also extract sharp bounce without going particularly short. Josh Hazlewood found that out in the second Test, when a back-of-a-length delivery outside off climbed on him as he attempted a cut. The resulting edge flew to second slip, giving Jansen the final wicket of the innings.

For all the variations, however, the good-length delivery remained Jansen's most reliable weapon. He bowled 283 balls in that area across the series, taking four wickets at an average of 22.5 and conceding just 1.9 runs per over. His full deliveries brought the same number of wickets from 107 balls, but at an economy of 4.3 per over. The difference, then, was how often he returned to the good length and kept batters quiet.

Ultimately, Jansen’s height gives him a natural edge, but it is how he uses it that sets him apart. He has maintained a similar pace while finding increasingly effective ways to exploit his natural bounce, making him a threat across different lengths and conditions. At 26, he has already established himself as the world’s leading Test bowler, but there is a sense that he is still discovering just how much more he can do with the ball in hand.