|World Cup Pool B, Melbourne Cricket Ground|
|India 307-7 (50 overs): Dhawan 137, Rahane 79|
|South Africa 177 (40.2 overs): Du Plessis 55, Ashwin 3-41|
|India won by 130 runs|
Shikhar Dhawan hit a superb century as defending champions India maintained their unbeaten start to the World Cup with a 130-run win over South Africa.
India's 307-7 was built around Dhawan's 137, while Ajinkya Rahane made 79 off 60 balls and Virat Kohli 46.
South Africa were bowled out for 177 with 9.4 overs unused as Faf du Plessis's departure for 55 sparked a collapse of seven wickets for 44 runs.
The defeat was South Africa's heaviest in World Cup history.
India, who remain top of Pool B with two wins from two games, face the United Arab Emirates in Perth on Sunday, when victory will all but secure their place in the quarter-finals.
Fifth-placed South Africa play West Indies in Sydney on Friday, but the manner in which they subsided on a blameless surface cast doubts on their tag as one of the pre-tournament favourites.
|Ex-England spinner Graeme Swann on Test Match Special|
|"India look like the team from this group who can go on and challenge New Zealand and Australia. Shikhar Dhawan was magnificent but so was Ajinkya Rahane - he's a small man in stature but he just smashed it."|
Dhawan's composed innings was typical of a measured rather than explosive batting display, and two run-outs in a crucial phase of the innings were reward for the pressure India created with an accomplished performance in the field.
"South Africa are such a good side, so I think that makes it an even more satisfying win," said India captain MS Dhoni, whose side beat Pakistan in their opening game.
"It was a back-to-back good performance from both the bowling and batting unit. A couple of run-outs made things even more impressive."
Dropped on 53 by Hashim Amla and fortunate not to be run out for 55, left-hander Dhawan combined fluent drives with meaty pulls in a 146-ball innings which featured 16 fours and two sixes.
Having lost Rohit Sharma cheaply after India won the toss, he added 127 with Kohli for the second wicket and 125 in 16 thrilling overs with Rahane for the third.
Dhawan eventually fell to a top-edged pull off Wayne Parnell, whose treatment late in the innings left him nursing figures of 1-85 off nine overs.
|Ex-South Africa batsman Barry Richards on Test Match Special|
|"The two things that always worry me about India cricket are running between the wickets and their ability to defend a target up front with their opening bowlers. They've dispelled both of those myths tonight. Their running was exceptional and their out-fielding was incredible."|
The Proteas' options were limited by the absence of seamer Vernon Philander, who bowled only four overs because of a hamstring injury and will have a scan on Monday.
No South Africa batsman came close to playing with the composure shown by Dhawan as India's fielders maintained the pressure created by Mohammed Shami's early removal of Quinton de Kock.
Mohit Sharma had Hashim Amla taken at long leg and Du Plessis drilled the first ball of his second spell to mid-off, either side of Mohit's most important contribution, running out South Africa captain AB de Villiers for 30 with a magnificent flat throw from deep point.
Smart work from Umesh Yadav and Dhoni accounted for the dangerous David Miller, and off-spinner Ravichandran Ashwin hastened South Africa's collapse to finish with 3-41.
South Africa's previous heaviest World Cup defeat was by 83 runs to Australia in Basseterre in 2007.
"The run-outs cost us dearly, coming just when we got started with the bat in hand. That's where we lost the game," said De Villiers.
"It was not a good enough performance as a batting unit and now we have to regroup."