CARDIFF: It may be too late — much too late — but South Africa finally kick-started its Cricket World Cup campaign with a nine-wicket win over Afghanistan under the DLS method at Sophia Gardens on Saturday.

Quinton de Kock hit 68, including eight fours, and Hashim Amla was 41 not out in South Africa's 131-1 in 28.4 overs in reply to Afghanistan's 125 all out in 34.1 overs.

The 40-year-old leg-spinner Imran Tahir did most of the damage for South Africa, finishing with 4-29 off seven overs, and captain Faf du Plessis was a happy man at the end.

"Very relieved. Feel a little bit lighter," du Plessis said. "But I think all our cricket today was much better and much more competitive."

Because of two rain disruptions, the match was reduced to 48 overs per team with South Africa chasing a new target of 127.

Andile Phehlukwayo (17 not out) sealed victory by smashing the only six of the game.

Amla was cautious but effective in his 83-ball knock which took him to within 24 of the 8,000 ODI runs milestone.

De Kock's innings lasted 72 balls and he shared an opening partnership of 104 with Amla before he was caught by Mohammad Nabi off the bowling of Gulbadin Naib in the 23rd over. It was South Africa's first century stand of the tournament.

After defeats to England, Bangladesh and India, and a washout against West Indies, this was a must-win game for four-time semifinalist South Africa.

But it still looks unlikely to advance to the final four. South Africa is level on three points in the bottom half of the table with West Indies, Bangladesh and Pakistan but has played one more game.

Afghanistan, which has lost all four matches and remains last in the 10-team standings, won't forget its first-ever one-day international against South Africa.

Put in to bat, Afghanistan was all out after collapsing from 69-2.

Tahir took a wicket with his first ball, and claimed a second in the same over, after the second rain break. He also preserved his record as the only spinner at this World Cup to have bowled more than 100 overs and not been hit for six.

"Imran, as always, is special, but I think especially on a wicket like that today where it's not suited for spinners, straight boundaries, to get four wickets like that was an amazing bowling performance," du Plessis said.

Seamer Chris Morris was even meaner than Tahir, taking 3-13 in 6.1 overs, and Phehlukwayo finished with 2-18 from eight overs.

Before the second break for rain, Afghanistan appeared on the brink of building a reasonable score. However, it lost four wickets in 10 balls for a single run at one stage and stumbled to 77-7 before staging a mini-recovery as Ikram Ali Khil and Rashid Khan shared a 34-run partnership for the eighth wicket.

Rashid top-scored for Afghanistan with 35 off 25 balls, including six boundaries, followed by Noor Ali Zadran's 32 runs off 58. Both men fell to Tahir.

Afghanistan had also failed to use up its batting overs in its previous three games, reaching 207 in 38.2 overs against Australia, 152 in 32.4 versus Sri Lanka and 172 in 41.1 against New Zealand.

Rain and Afghanistan clearly do not get on at this tournament. The first weather interruption, a 26-minute delay, disturbed a promising start as the team had advanced to 33-0 off 5.5 overs.

Opener Hazratullah Zazai pulled a delivery from paceman Kagiso Rabada and was caught by Rassie van der Dussen running in from the boundary for 22 off 23 balls. Rahmat Shah was then out leg before wicket to an impressive Morris for a 22-ball 6.

The second break did even more damage. Afghanistan captain Naib said: "Maybe it's a turning point there ... when the rains come."

South Africa kept an unchanged lineup from its washout against West Indies, with fast bowler Lungi Ngidi given more time to recover from a hamstring injury.

Afghanistan made one change from its seven-wicket defeat to New Zealand, bringing in former captain Asghar Afghan and dropping batsman Najibullah Zadran.

Afghanistan next plays England in Manchester on Tuesday, and South Africa faces New Zealand in Birmingham on Wednesday.