Cape Town - Centuries to Quinton de Kock and Hashim Amla paved the way for a comfortable seven wicket victory over England at SuperSport Park in Centurion on Tuesday.
It certainly didn't look that way after England had won the toss and opted to bat on a strip renowned for its high scoring characteristics.
Led by a brilliant 125 by Joe Root, England built a number of partnerships on their way to posting an imposing 318/8 in their 50 overs.
Root first combined with Alex Hales, with the pair putting on 125 for the second wicket in just 20.3 overs.
Kagiso Rabada then fired the Proteas back into the match with two quick wickets, removing Hales (65) and the dangerous Jos Buttler (0) while David Wiese had Eoin Morgan caught for 7.
Root, however, had no trouble with the Proteas attack.
He was joined by Ben Stokes (53) and the pair put on 82 for the 5th wicket at over 9 runs per over with Root moving to his century of 95 balls, including 8 fours and 3 sixes.
The Proteas managed to pull the scoring rate back by taking regular wickets during the final ten overs, but some lusty hitting by Adil Rashid (13*) and David Willey (13*) at the death saw England well passed the 300 mark.
Kyle Abbott (2/50 in 10 overs) and Rabada (2/65 in 10 overs) were the pick of the Proteas bowlers.
With a weakened batting lineup, the Proteas would need an excellent start which De Kock and Amla provided.
After a watchful period in the opening five overs, the Proteas openers were soon on their game, with De Kock in particular punishing anything short, overpitched or offline from the England bowlers.
De Kock was first to reach his 50 of just 57 balls while Amla was prepared to play the anchor role.
With the threat of rain, the two increased their scoring rate to ensure the Proteas stayed well ahead of the Duckworth-Lewis par score.
Amla was next to a milestone, reaching his 50 of 63 balls while De Kock continued to push towards his hundred.
The Proteas wicket-keeper became a little becalmed in the nineties, but soon he reached his 10th ODI century off just 96 balls with 11 fours and 3 sixes.
De Kock continued to play freely, but fell to Moeen Ali for 135 after trying to clear mid-off only to be caught by Root.
De Kock and Amla had put on an astonishing 239 for the first wicket placing them eighth on the list of all-time first wicket partnerships in one-day internationals.
Surprisingly, David Wiese was next in and he didn't last long.
After depositing Ali into the crowd at long-off for a huge six, Wiese tried and ill-judged reverse sweep, only to be bowled for 7.
Amla moved to his 22nd ODI century off 108 balls with 10 fours and a six and together with Faf du Plessis (33*) ensured the Proteas would have no late innings jitters.
Amla fell for 127 but by that time, victory was well within sight of the Proteas and Du Plessis duly hit the winning runs in the 47th over.
England now lead the series 2-1 going into Friday's fourth ODI at the Wanderers but the Proteas will feel the momentum has now shifted in their favour.