Ashwell Prince [ Images ] scored his maiden half-century to steer South Africa [ Images ] to a three-wicket win over England [ Images ] and wrap up a 4-1 series victory in the seventh and final one-day international on Sunday.
Despite a superb century under pressure by England's Kevin Pietersen [ Images ], who lifted England to 240 all out in 49.5 overs, South Africa won with an over to spare after Prince struck a career-best 62 not out in 76 balls.
Pietersen smashed 116 off 110 balls -- his third century of the series -- to lift his series aggregate to 454 runs at an average of 151 after coming to the crease with his side 32 for three.
Ashley Giles (41) and Kabir Ali (25) combined with the South African-born Pietersen in crucial lower-order stands of 104 for the seventh wicket and 53 for the eighth.
Boucher scored his 44 off just 40 balls with six fours before he was run out when 23 runs were still needed, though he had got South Africa near enough to their victory target and, while Justin Kemp and Shaun Pollock [ Images ] were dismissed cheaply, Prince got them home safely.
South Africa shuffled their batting order with Andrew Hall (23) opening with Smith, and the pair put on a confident 46 in 10.4 overs for the first wicket before Hall was brilliantly caught at deep square-leg by Steve Harmison [ Images ] off Alex Wharf.
Smith continued to attack the England bowlers, scoring his 47 off 66 balls, with six fours, before he gifted Giles his wicket by holing out at mid-off.
Kallis also got himself out, hitting Michael Vaughan's [ Images ] first ball to long-on for 36, while Herschelle Gibbs [ Images ] was out lbw for a duck to Harmison before Prince and Boucher ensured the win.
Earlier, Pietersen rescued the visitors after they had slumped to 32 for three then 68 for six before he combined with Giles and Ali to provide some respectability to their score.
Pietersen, who reached his half-century off 80 balls, launched into all-out aggression in the last 10 overs, needing just 24 more balls to reach his century. He hit 10 fours and cleared the boundary six times.
M.Trescothick c Gibbs b Pollock 0
G.Jones c Kemp b Nel 14
M.Vaughan b Ntini 1
A.Strauss c Boucher b Nel 15
K.Pietersen b Hall 116
V.Solanki c Smith b Boje 5
P.Collingwood run out (Smith) 10
A.Giles b Ntini 41
K.Ali b Hall 25
A.Wharf not out 3
S.Harmison b Hall 0
Extras (nb-3 w-7) 10
Total (all out, 49.5 overs) 240
Fall of wickets: 1-0 2-1 3-32 4-36 5-54 6-68 7-172 8-225 9-240
Bowling: Pollock 10-1-36-1 (nb-2), Ntini 9-2-47-2 (w-3), Nel 10-1-60-2 (w-1), Hall 9.5-1-52-3 (nb-1 w-2), Boje 10-0-34-1 (w-1), Kallis 1-0-11-0
G.Smith c Solanki b Giles 47
A.Hall c Harmison b Wharf 23
J.Kallis c Trescothick b Vaughan 36
H.Gibbs lbw b Harmison 0
A.Prince not out 62
M.Boucher run out (Strauss) 44
J.Kemp c Giles b Ali 4
S.Pollock c Collingwood b Wharf 6
N.Boje not out 1
Extras (lb-2 nb-2 w-14) 18
Total (for seven wickets, 49 overs) 241
Fall of wickets: 1-46 2-106 3-107 4-148 5-218 6-228 7-236.
Did not bat: M Ntini, A Nel
Bowling: Wharf 10-2-51-2 (nb-2 w-1), Harmison 10-0-55-1 (w-8), Ali 9-0-48-1, Collingwood 5-0-25-0 (w-5), Giles 10-0-38-1, Vaughan 5-0-22-1
Result: South Africa won by three wickets
Series: South Africa win series 4-1