South Africa 182 for 6 (Hendricks 42, Klaasen 39, Delany 2-24) beat Ireland 138 (Tector 34, Parnell 5-30, Pretorius 3-33) by 44 runs
Bristol: South Africa beat Ireland by 44 runs to complete a double in the Twenty20 series in Bristol.
In-form opener Reeza Hendricks top-scored with 42 for the Proteas, for whom Heinrich Klaasen contributed 39, as they set a target of 182-6.
Andy Balbirnie and Lorcan Tucker both failed to score as Ireland languished at 2-2 in reply but Paul Stirling's 28 and Harry Tector's 34 saw them rally.
Barry McCarthy's stubborn resistance with 32 helped Ireland to 138 all out.
Despite that gutsy effort from the tail-ender, Ireland were bowled out with seven balls to spare.
Wayne Parnell's maiden five-wicket T20 international haul proved crucial, the left-arm quick taking 5-30 to help inflict an eighth successive defeat for Ireland at this level.
Parnell put a dent in Ireland's chase early on, taking two wickets in consecutive balls.
Balbirnie fell for an eight-ball duck when he chipped to cover and Tucker, fresh from his 78 in the first T20, which Ireland lost by 21 runs, went first ball when he miscued to mid-on.
The in-form Tector survived the hat-trick, and with the experienced Paul Stirling started to repair the damage.
Stirling had hit two fours and two sixes in a score of 28 when he was struck a painful blow in the groin after missing a pull off fast bowler Lungi Ngidi.
The next ball proved his undoing, with Stirling slicing a well-disguised slower ball from Ngidi and Aiden Markram, running from point towards short third man, taking the catch.
Ireland were 40-4 when Gareth Delany was lbw for a duck to left-arm wrist-spinner Tabraiz Shamsi.
Parnell then took two wickets in three balls, with Curtis Campher caught behind on the reverse sweep before Tector holed out off a miscued pull for 34.
Then, in his 45th match at this level, Parnell had a fifth wicket when Andy McBrine was brilliantly caught by diving wicketkeeper Quinton de Kock.
That left Ireland 96-9 and while McCarthy's late knock entertained the crowd, it merely delayed defeat.
Earlier, South Africa captain David Miller marked his return with an unbeaten 32 and a rapid stand of 71 in 33 balls with Klaasen that helped the Proteas post their target.
Miller, who missed Wednesday's match with back spasms, hit three sixes after tight Ireland bowling had initially left South Africa struggling for runs, with opener De Kock again out cheaply.
Klaasen's 39 took only 16 balls after Hendricks had just fallen short of a fifth successive T20 international fifty when out for 42.
But Ireland pulled things back in the field following leg-spinner Delany's 2-24.
This was South Africa's last match at this level before they finalise a squad for the T20 World Cup, which will go to India for a three-match series in September ahead of the showpiece tournament in Australia.
Ireland are at home to Afghanistan in a five-match series later this month.