South Africa wrapped up the Zimbabwe innings for 136 in 37.2 overs, comprehensively outplaying their neighbours to win the first one-day international by 165 runs on Friday.
After battering 301 for seven in their 50 overs, South Africa bowled and fielded efficiently.
Zimbabwe will be disappointed none of their batsmen managed to pass 30, captain Tatenda Taibu scoring 28 and opener Stuart Matsikenyeri 25.
Fast bowler Makhaya Ntini took three for 42 for South Africa after rapid half-centuries by Graeme Smith (50), Adam Bacher (56) and Jacques Rudolph (50) had set up their total, aided by 49 from Mark Boucher.
South Africa's second-string attack, missing Shaun Pollock, Andre Nel, Charl Langeveldt and Jacques Kallis, was still too much for Zimbabwe's batsmen to handle.
At 55 for four in the 13th over, the match was firmly in the home side's control and Albie Morkel virtually sealed matters when he took two wickets in the 20th over.
Zimbabwe were 75 for six and although Taibu and Sean Williams added 35 for the seventh wicket, the last three wickets were taken for 26.
South African captain Smith said: "I don't know if it was because of all the rain the past week, but the facilities weren't great.
"The pitch was slow and up and down. A lot of balls kept low and others took off from the cracks and Mark Boucher played superbly to get us to 300."
The second one-dayer is on Sunday in Durban where Zimbabwe will be heartened that Heath Streak is back in the fold after news that he has signed a contract to play for his country again after a year-long exile.
G.Smith lbw b Matsikenyeri 50
A.Bacher c Masakadza b Utseya 56
J.Rudolph c Matsikenyeri b Utseya 50
H.Gibbs c Maragwede b Rogers 40
J.Kemp st Taibu b Utseya 8
M.Boucher b Chigumbura 49
A.Prince not out 20
A.Morkel c Masakadza b Panyangara 16
N.Boje not out 4
Extras (lb-2 nb-1 w-5) 8
Total (for 7 wkts, 50 overs) 301
Did not bat: A.J.Hall, M.Ntini
Fall of wickets: 1-87 2-128 3-184 4-197 5-223 6-276 7-297
Bowling: Panyangara 10-1-64-1 (nb-1, w-1), Mpofu 6-0-44-0 (w-1), Chigumbura 8-0-45-1 (w-3), Matsikenyeri 9-0-62-1, Utseya 10-0-40-3, Williams 3-0-16-0, Rogers 4-0-28-1.
S.Matsikenyeri c Gibbs b Ntini 25
B.Rogers c Boje b Hall 1
H.Masakadza c Rudolph b Ntini 10
A.Maragwede lbw b Morkel 16
B.Taylor c Smith b Hall 3
T.Taibu c Smith b Boje 28
E.Chigumbura c Prince b Morkel 0
S.Williams run out (Boje) 12
T.Panyangara b Ntini 9
P.Utseya b Hall 11
C.Mpofu not out 1
Extras (b-2 lb-8 w-10) 20
Total (all out, 37.2 overs) 136
Fall of wickets: 1-4 2-36 3-41 4-55 5-75 6-75 7-110 8-113 9-121 10-136.
Bowling: Hall 7.2-1-29-3 (w-3), Ntini 10-0-42-3 (w-3), Morkel 6-1-23-2 (w-4), Boje 9-1-21-1, Bacher 2-0-6-0, Kemp 3-0-5-0.
Result: South Africa won by 165 runs.