Handre Pollard claimed a 20-point haul as South Africa beat Wales 30-14 to win the Test series in Cape Town on Saturday.
Wales secured a historic first victory in South Africa last weekend to set up a decider at DHL Stadium, but the world champions outscored Wayne Pivac's side three tries to one to take the series 2-1.
Pollard put the Springboks in front with an early penalty and the fly-half then powered over from close range for a try following a sustained period of pressure.
Wales hit back courtesy of Tommy Reffell's first international try and Dan Biggar's penalty reduced the deficit to two points after South Africa lost Cheslin Kolbe to injury.
But the world champions were outmuscling the tourists at the set-piece and Bongi Mbonambi marked his 50th Test by charging over from the back of a ruck following a lineout late in the first half.
Another two Biggar penalties made it 17-14, but captain Siya Kolisi crossed after South Africa went through the phases just before the hour mark and Pollard added the extras.
Eben Etzebeth was then given a great ovation after he was replaced in his 100th Test, with the excellent Pollard making no mistakes with another two penalties late on as the Springboks deservedly wrapped up the series.