Sangakkara and Jayawardene completed the win

Sri Lanka extended their unbeaten run against South Africa with a seven-wicket win in the fourth one-day match.

The hosts passed the target of 236 with 23 balls to spare after an unbroken stand of 98 between Kumar Sangakkara (74) and Mahela Jayawardene (48)

Shaun Pollock hit a brisk 52 to steer South Africa to 235-7 after the tourists had lost three quick wickets.

Captain Graeme Smith (46) was the first of two wickets in an over for leg-spinner Kaushal Lokuarachchi.

Resting four key players including captain Marvan Atapattu, the start their run chase badly when opener Sanath Jayasuriya was run out after a mix-up with Avishka Gunawardene.

It is a nightmare for us at the moment - I don't know what we have to do Graeme Smith Reaction from both teams

But Gunawardene, who survived two difficult slip chances on 13 and 32, fought back to score 52 from 64 balls, hitting seven boundaries.

Straight after the first drinks break, the left-hander nicked a catch behind off Makhaya Ntini to but Saman Jayantha shared a 65-run stand with Sangakkara.

After a slow and nervous start, during which he was dropped behind on 12 and fortunate not to be adjudged lbw on 15, Jayantha went on to 46.

Sangakkara took the man of the match award after an 86-ball innings that included six fours.

Earlier, South Africa captain Graeme Smith led from the front with 46 from 64 balls, sharing a 47-partnership for the first wicket with Herschelle Gibbs.

But a mid-innings wobble, during which three wickets tumbled for two runs, left the tourists in trouble on 115-5.

Jacques Rudolph was run out by Farveez Maharoof then Lokuarachchi - a late inclusion for the ICC Champions Trophy to replace the injured Muttiah Muralitharan - trapped Smith and Jean-Paul Duminy lbw.

Pollock resuscitated the innings in a 64-run stand with Mark Boucher and guided South Africa to a competitive total with a late surge as 49 runs were plundered from the last five overs.

Sri Lanka: Mahela Jayawardene (captain), Sanath Jayasuriya, Saman Jayantha, Kumar Sangakkara, Tillakaratne Dilshan, Avishka Gunawardene, Farveez Maharoof, Lasith Malinga, Upul Chandana, Kaushal Lokuarachchi, Dilhara Fernando.