New Zealand and South Africa both recovered from narrow first-half deficits to beat Australia and Argentina respectively and get their Rugby Championship campaigns off to a winning start.

A strong second-half performance brought the All Blacks five tries in Sydney and a 38-13 victory after they had trailed 6-5 at half-time.

Aaron Smith opened their try account on the stroke of half-time following two penalties from the Wallabies, before Jack Goodhue, Beauden Barrett, Brodie Retallick and Waisake Naholo, with a brace, helped second-row Sam Whitelock celebrate his 100th cap in style.

The win is worth just over half a rating point and extends New Zealand’s cushion over Ireland at the top of the World Rugby Rankings to 4.4 points.

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South Africa recovered from the setback of conceding first-half tries to Nicolas Sanchez and Pablo Matera to ease to a 34-21 win over Argentina at Kings Park in Durban.

New Los Pumas coach Mario Ledesma was on course to mark his first match in charge with a morale-boosting win as his side led 14-10 at the break, but two tries apiece from Aphie Dyantyi and Makazole Mapimpi, bookended by scores from centre Lukhanyo Am and Faf de Klerk, ensured the Springboks built on their 2-1 series win over England in June.

South Africa do not receive any rating gain for the victory, due to the large points differential between themselves and Argentina, with the sides remaining in fifth and 10th place respectively.

Further boost for Namibia

Also on Saturday, Namibia confirmed their place at RWC 2019 in Pool B alongside New Zealand, South Africa, Italy and the Repechage Winner after retaining the Rugby Africa Gold Cup with an emphatic 53-28 victory over Kenya.

The result lifts the Welwitschias above Canada in the rankings to 22nd place, and they are now less than half a point away from catching Hong Kong in 21st. Kenya remain in 28th place despite the loss of nearly six-tenths of a point.

Kenya will now play Canada, Hong Kong and Germany for the right to claim the 20th and final ticket to Japan at the RWC 2019 repechage tournament in November.

After securing their place in the Gold Cup for next season with a 38-18 win away to Uganda, Zimbabwe climb eight places in the rankings to 37th.  Uganda fall six places to 41st.

Tunisia also live to fight another day in Africa’s top-tier competition, thanks to their 36-13 win over Morocco, and as an added bonus they climb two places to 40th, overtaking Sri Lanka and Colombia in the process.

Morocco's fall of four places to 47th sees the Ivory Coast and Guyana shift up one, to 45th and 46th respectively.