And we thought Senuran Muthusamy had been selected as a bowler in Rawalpindi. Turns out he is really an innings-resurrector, a lead-getter, a strong, stable, patient batting partner.

Bowling? He was given a scant four overs in the first innings, and he has had another four in the second. That, mind, from someone who claimed 6/117 and 5/57 in Lahore last week.

South Africa were 148 behind with five down when Muthusamy took guard to face the second ball of the third day's play on Wednesday. He was still there when the innings ended shortly before tea, having gritted through more than three-and-a-half hours and faced 155 balls for his unbeaten 89.

Muthusamy's stands with Tristan Stubbs, Simon Harmer and Marco Jansen amounted to 50 runs. At 235/8, it seemed the visitors would be dismissed significantly in arrears of Pakistan's 333.

Muthusamy had faced 60 balls for his 27 not out when Noman Ali trapped Jansen in front. Then the magic happened.

Keshav Maharaj, always a punchy batter, showed enough discipline to score 30 off 53 before he lurched down the pitch to Noman and was stumped. That put paid to a partnership of 71 in which Muthusamy ticked along at the rate of 35 off 39.

Maharaj's dismissal left the South Africans nine down and still 27 behind. Enter Kagiso Rabada to deliver the batting performance of his life.

"KG was exemplary," Muthusamy told a press conference. "It was an innings of the highest standard. His ball-striking in those conditions was superb. He's such a naturally free-flowing batter.

"The plan was to keep batting and keep the tempo we were going at, but I ended up playing a supporting role as the innings went on because he was seeing it so nicely and hitting it so cleanly. I lost rhythm towards the end of my innings. I found it tough to score, especially with the field spread and almost everybody on the boundary."

With the entrenched Muthusamy applying himself impeccably and Rabada booming drives down the ground seemingly at will, the last wicket realised 98 off 117. Muthusamy scored 27 of them off 56. Rabada hammered 71 off 61 with four fours and as many sixes - one of the latter straight and true off Shaheen Shah Afridi with textbook technique.

Strokes like that made Shaun Pollock dub Rabada South Africa's Brian Lara. Pollock is the most measured and uncontroversial of commentators. For him to say something like that, even in mild jest, was as stupendous as Rabada's batting itself.

The partnership was a mutually beneficial relationship, a kind of codependency. Muthusamy wouldn't have been able to give nothing away as resolutely as he did if the runs weren't coming from the other end. Rabada wouldn't have been able to play with such sweet freedom if he didn't have full faith in his partner to stay there.

The party kept going long enough to earn a lead of 71. It was a busy day for that number, which was also the value of the Muthusamy-Maharaj stand and Rabada's score.

Perhaps more pertinently, South Africa have batted second in three other Tests in Pakistan. This is the first time they have been ahead after the first innings. Only once in their 11 Tests in the country have they totalled more than the 404 they were bowled out for on Wednesday.

The plug was pulled when Rabada tried to put Asif Afridi over long-on for six and was caught on the boundary. That gave Asif, a 38-year-old debutant, 6/79 - which made him the oldest man to take a five-wicket-haul in his first Test.

Pakistan looked in no mood to help him celebrate. Their opponents' last two pairs had batted for two hours, added 169 runs, and seized the advantage for their team.

The home side were still rattled when they came out to bat, and crashed to 16/3 inside the first seven overs, which were bowled by Rabada and Harmer.

Babar Azam and Saud Shakeel nursed Pakistan back into the lead, but they were reduced to 60/4 with the 13th ball after the day's last drinks break when Shakeel edged to first slip to earn a third wicket for Harmer.

Pakistan will resume with a lead of 23 and with Barbar, who looms as the key to the outcome of the match, one run short of a half-century. If South Africa get him early the game is as good as theirs. Allow him to reach, say, 71 and the home side will breathe easier.