Gibbs patiently worked the ball around on a slow wicket

Herschelle Gibbs' unbeaten 93 helped South Africa to defeat India by 80 runs in the fourth one-day international and clinch the series.

The hosts won the toss and made 243-8 from their 50 overs and then dismissed their opponents for 163 in 38.1 overs at St George's Park in Port Elizabeth.

Irfan Pathan was still at the crease on 47 when he ran out of partners.

South Africa now have an unassailable 3-0 lead in the series which ends on Sunday. The first match was rained off.

Despite their comfortable winning margin, the hosts had looked to be in trouble when Graeme Smith and Loots Bosman fell for ducks.

"We're winning and we're not playing our best cricket, which is great Herschelle Gibbs

But Gibbs put on 69 with Jacques Kallis (49) and 61 with Mark Boucher, while Shaun Pollock later hit a quickfire 37.

Proteas skipper Smith fell lbw to the third ball of the game from Zaheer Khan.

Bosman was then clean bowled by a Shanthakumaran Sreesanth yorker in the next over.

Kallis responded with nine boundaries in his 62-ball knock before edging behind in an attempt to force away Anil Kumble's first ball outside off-stump.

Pathan's single-handed resistance was not enough for India

AB de Villiers thumped the spinner over long-off for six but missed with an attempted sweep to fall lbw.

Stand-in skipper Virender Sehwag then had Boucher plumb lbw playing across the line.

He followed up by catching Justin Kemp first ball when he chopped Sachin Tendulkar straight to him at point.

At 155-6 the Indians sensed an opening, but Gibbs stood firm.

He recovered from being caught off a Sreesanth no-ball on two to patiently work the ball around and collect eight boundaries off 123 balls.

Pollock provided the late flourish, clubbing Sehwag and Tendulkar over the long-on fence in a 43-ball cameo.

Kumble was the pick of India's bowlers, with 2-42 of 10 overs.

India made a promising start, with Wassim Jaffer and Sehwag putting on 23 before Jaffer was caught at slip off Makhaya Ntini in the sixth over.

"Our batting was disappointing, especially in the top order, and we hardly put a partnership together India skipper Virender Sehwag

But the contest was effectively dead within four overs, with Sachin Tendulkar and Sehwag falling to Pollock and Ntini respectively.

Mohammad Kaif was run out and Mahendra Dhoni played one extravagant shot too many as India slumped to 82-5.

Justin Kemp took three wickets and Pollock and Ntini two each, with only Pathan offering any resistance.