South Africa thought it would take two bowlers to make up for Kagiso Rabada's absence. It almost took too many.

After Morne Morkel and Vernon Philander did with the new ball what bowlers of their quality and experience tend to do with the new ball and made it "talk", South Africa would ordinarily have had Rabada to continue the conversation. Instead, they had Chris Morris, who has only played in two first-class matches apart from the Worcester tour match since making his Test debut in January 2016, and Duanne Olivier, who has played in just five first-class matches since his first cap in January this year. To say the pair were undercooked would not be overstating things.

Morris started too short and stayed there with 23 of his 53 deliveries pitched either back of a length or short. By comparison, Morkel bowled only 12 deliveries in the same area out of the 78 he sent down, a lesson that fuller was going to be key on this pitch. Faf du Plessis tried to set fields for the short-ball trap, routinely moving his fine leg in the hope Joe Root would pick him out, but it was not the ideal way to be strategising. And while Morris struggled with length, Olivier battled to find the right line. In the six overs after the opening pair's initial spells, South Africa conceded 41 runs.

A band-aid over of spin took the teams into the lunch break and allowed the frontline quicks to rest up. They needed it because more was demanded of them after the interval. While Philander bowled a four-over post-lunch spell, Morkel was asked for double that to keep the pressure on, at least from one end.

The extended spell proved crucial because it was during that period that Morkel removed Root, the biggest threat to South Africa's chances of taking the lead, but not the only one. England's middle-order packs a powerful punch and Root's scoring rate had given them the platform to counterpunch.

So du Plessis had a conundrum on his hands. With Morkel needing a break and Philander taking over from his end, he needed to plug a gap on the other side. He could not go back to Morris, whose first three overs cost 20, or keep Olivier, whose wretched time had only continued. On a seamer's surface, half of South Africa's pack seemed to be wasting their chances, so it was the spinner who had to do the job.

Keshav Maharaj is not a huge turner of the ball - except at Lord's last week when he managed to get one to land on middle and veer to slip early on - but he is disciplined and consistent. He finds decent areas, does not offer many scoring opportunities, and benefits when batsmen get frustrated. It's easy to underestimate the impact he can have and that may have been what Ben Stokes did.

After 37 minutes at the crease, Stokes had only faced 11 balls and had not scored a run when Maharaj drew him forward with a ball that was placed just outside off. Stokes got an inside-edge that bounced off his pad to de Kock - almost via the grille - to give South Africa an all-important "in". Though Stokes has not done extensive damage with the bat in this series, South Africa know what he is capable of. Du Plessis had even nicknamed him "the dragon", for his ability to breathe fire into a performance. Getting rid of him for a duck put South Africa in a position from which they could think about taking control.

Within four overs, that thought became reality when Maharaj manufactured his next bit of magic. For all that's been said about his unspectacular style, in his last over before tea, he found drift and turn and beat Jonny Bairstow's inside-edge to bowl him and put South Africa well ahead, with room to manoeuvre. They did not need to rely on the 20 minutes between the afternoon and evening sessions for Philander and Morkel to freshen up because Maharaj had done a good enough job to hold up an end so that the quicks could rotate at the other.

After tea, however, instead of starting with the obvious choice - Morkel to mop up - du Plessis made a bold move and brought back Morris. Having kept Morris out of the game, the captain deemed it safe to reintroduce him and his reading of the situation was entirely correct. Morris will now remember this innings because he was on a hat-trick at one stage - having dismissed Moeen Ali and Stuart Broad in successive deliveries with full balls (hint, hint) - and not because he was carted around for more than six runs an over at another. His confidence will have been boosted because he repaid du Plessis' faith in him and contributed to securing a big lead.

But the real hero of the second half of the South African bowling performance is Maharaj. Like so many South African spinners, he goes about his business almost unnoticed but he is anything but an afterthought. At his worst, he has simply kept things tight, and has only cost South Africa more than three-and-a-half runs an over twice in his nine Test career. At his best, he keeps the pressure on an opposition and forces them into making mistakes. His 15 wickets in three Tests in New Zealand in March is evidence of that.

Unlike his most immediate predecessors - Dane Piedt, Imran Tahir and Simon Harmer - Maharaj is not simply a supporting actor. He is reliable and relentless and, though he and Rabada have very little in common when it comes to their bowling, today Maharaj's work more than made up for Rabada's absence.