If Shaun Pollock couldn't quite work out how South Africa contrived to lose the sixth and final Standard Bank one-day international at the Wanderers on Wednesday, then neither could Sri Lankan captain Sanath Jayasuriya fathom how the side batting second in a rain-interrupted game were required to score fewer runs than their opponents in the same number of overs.

The Sri Lankan victory, coming after Pollock tried and failed to win the match with a six off the last ball from, fittingly, Jayasuriya ended a sequence of 10 straight wins for South Africa. If this was a disappointment, then at least Pollock could take comfort from his side's 5-1 win in the series and the naming of Jacques Kallis as the man of the series.

It was a match which, in all honesty should have been won at a canter. With eight overs remaining, South Africa needed 40 to win with six wickets standing. Then Jonty Rhodes got himself bowled trying to reverse sweep Muttiah Muralitharan to precipitate a collapse which ended with Pollock needing to hit 11 off the last two balls of the game.

He hit the penultimate delivery back over Jayasuriya's head for six, but scuffed the last one back to the bowler for Allan Donald to be run out and that was that.

South Africa had been required to score 209 off 42 overs to win after Sri Lanka had made 214 for six off 42 overs. This is where Duckworth and Lewis arrived to baffle everyone.

Apparently the calculation took into account that Sri Lanka were 21 for three off nine overs when a thunderstorm stopped play for two hours. But why this was no one could explain.

"You tell me," said Jayasuriya afterwards. "The team batting second always has to score more runs, not less. I don't understand this."

Neither, apparently, did match referee Ramon Subba Row who called for the United Cricket Board's director of umpiring, Brian Basson, to explain the lie of the lands to the bewildered Sri Lankans.

Russel ArnoldPhoto CricInfo

In the end it made no difference with Sri Lanka scrambling to an unlikely victory, but one which owed a great deal to Man of the Match Russel Arnold's unbeaten 65. The Sri Lankans seldom seemed in it after slumping to 20 for three, but Arnold, coming in at 85 for four, battered his runs off 56 balls. Even he, though, might not have been aware quite how valuable his innings was to become.

The dismissal of Rhodes was the turning point. South Africa had had Nicky Boje, with 46 off 50 balls, and Neil McKenzie add 76 for the fourth wicket in a partnership that seemed to have taken the game completely away from Sri Lanka. But when Rhodes went at 169 for five, he was followed quickly by Mark Boucher and Justin Kemp and then, crucially, McKenzie for 47.

Suddenly Pollock was left there with Donald, two balls remaining and 11 to get.

"Funnily enough I thought I could do it," said Pollock. "The six off the second last ball I didn't hit that well. It came of the bottom of the bat and I didn't think it would carry. But I couldn't do it again."

For the Sri Lankans, the win comes at a psychologically important time, just three days ahead of the third Test. But it may have come at a cost. Chaminda Vaas had to be helped off the field with what appeared to be a badly sprained groin. Jayasuriya said afterwards that it was too early to tell how severe the injury was, but from the way Vaas went down, he did not look likely to take any further part in the tour.

Then again, as Arnold said: "He's a good actor." Perhaps the Sri Lankans will still wheel him out at SuperSport Park on Saturday.