Reeza Hendricks (65 off 46) and Rassie van der Dussen (64 off 44) scored half-centuries, JP Duminy scored a 17-ball 33* and the bowlers got the better of every Sri Lankan player except Isuru Udana, whose 48-ball 84* went in vain.

The series-clinching victory – they have an unassailable 2-0 victory – means they have so far blanked Sri Lanka in the white-ball leg of their tour.

Duminy, standing in as captain with Faf du Plessis rested, was delighted the performance – “Always good to get a series win under the belt. All in all, a good team performance” – and said the 116-run partnership between Hendricks and van der Dussen set the game up for the hosts. That partnership set up the game nicely for us,” he said.

“He [Hendricks] is a quality player and you always knew something was going to turn for him.”

There was also praise for the bowlers: Dale Steyn snuffed out Avishka Fernando (0) and Kusal Mendis (4) to reduce Sri Lanka to 31/4 in four overs, while Morris saw off the dangerous Niroshan Dickwella (20 off 15) and added middle and lower order scalps to end with 3/32.

Despite Udana’s best efforts, the South African pacemen weren’t to be stopped. “That's quality – he (Steyn) is a match-winner. He always gives you something in the Powerplay,” said Duminy. “Udana played a fantastic innings. He got a few lives there, but in the end we will take the win.

"[As for Morris] he enjoys this sort of responsibility and tonight he was sublime. The confidence he showed today was amazing.”

The mood was different in the Sri Lanka camp. Not for the first time on this tour, Lasith Malinga, the Sri Lanka captain, called for better performances from the top-order batsmen.

“Very frustrating for us to lose games like these, especially with the top-order batsmen,” he said. “They have to learn what the team is expecting and provide good starts. The bowling went well, but towards the end, they got a few runs in the last three overs. They got 10 runs more than we expected.”

The final T20I will be played in Johannesburg on Sunday.