Ebullient hundreds of Smriti Mandhana and Harmanpreet Kaur were nearly upended by remarkable centuries from Laura Wolvaardt and Marizanne Kapp, but India kept their nerves to beat South Africa by four runs in a last-over thriller to take an unassailable 2-0 in ODI series in Bengaluru, on Wednesday.
India had beaten South Africa by 143 runs in the first match on Sunday.
It was a matter of margins once India posted an imposing 325 for three, riding on Mandhana's 136 (120b, 18x4, 2x6) and Harmanpreet's unbeaten 103 (88b, 9x4, 3x6), their seventh and sixth one-day tons respectively.
However, the Proteas fought back through Kapp (114, 94b, 11x4, 3x6) and Wolvaardt (135 not out, 135b, 12x4 3x6), who added 184 runs off 170 balls for the fourth wicket, but could manage 321 for six.
The Chinnaswamy pitch stayed truer as compared to the previous match, and the Indian bowlers had to be precise in their line and length on this day to be effective.
They did just that. At no point, the home bowlers allowed SA batters a free run, picking up wickets at regular intervals.
Pacer Arundhati Reddy, who replaced Renuka Singh, gave India a good beginning, beating the defence of Tazmin Brits with a delivery that came in by that bit.
However, Mandhana gave crowd the moment of the day when she accounted for Sune Luus, caught behind by Richa Ghosh, to bag her maiden international wicket.
That brought together Wolvaardt and Kapp, who resisted the Indian spinners with excellent footwork and shot selection.
Kapp, who made fifty off 53 balls, was the more aggressive of the duo, underlined by her two powerful pulls off Pooja Vastrakar that rocketed to the fence.
Wolvaardt gave Kapp solid support and brought up her fifty in 69 balls, as she touched the mark with a well-timed swat four to mid-wicket off Vastrakar.
They fetched 100 runs for the fourth wicket in 114 balls, when Kapp swept left-arm spinner Radha Yadav for a boundary.
The South African pair rarely played an aerial shot during their partnership but that survival-first approach also took the asking rate past nine and later 10.
The tourists required 103 runs in the last 10 overs and it did not look impossible with a set Kapp and Wolvaardt in the middle, but they had to take their chances for that.
Kapp, who reached her hundred in 85 balls and the enforcer of the alliance, went for the jugular against off-spinner Deepti Sharma but Vastrakar took a well-judged catch near the boundary to end the threatening stand.
Wolvaardt then combined with Nadine de Klerk to make 69 runs off 41 balls for the fifth wicket, but that was not enough on the night, as Vastrakar defended 11 runs off the last over.
Earlier, Smriti Mandhana's stylish seventh one-day hundred, her second in as many matches, and skipper Harmanpreet Kaur's belligerent century lifted India to a formidable 325 for three against South Africa .
Mandhana 136 (120b, 18x4, 2x6) and Harmanpreet 103 not out (88b, 9x4, 3x6), her sixth ODI ton, milked 171 runs for the third wicket, and ran roughshod over the Proteas bowlers after being asked to bat first.
South African skipper Laura Wolvaardt's decision to have a bowl seemed vindicated as new-ball bowlers, Ayabonga Khaka and Masabata Klaas, found appreciable bounce and movement under overcast skies.
In fact, Khaka started with two maidens in a row as Mandhana, whom she later dropped on 69 off left-arm spinner Nondumiso Shangase, and Shafali Verma struggled for a move-on.
India's first boundary came only in the sixth over, a pull by Shafali off Klaas, but the opener departed soon after being ousted by left-arm spinner Noku Mlaba.
A period of consolidation followed as Mandhana and Dayalan Hemalatha added 62 runs for the second wicket in which the latter was the more dominant presence.
Hemalatha (24), who clubbed Shangase for two sixes, looked good for more but her attempt to slog-sweep Klaas ended in the hands of Anneke Bosch.
However, the arrival of skipper Harmanpreet changed the complexion of the innings as run-rate of India, which was hovering around 4 till then, first soared past five and then six runs an over.
Mandhana hammered Shangase for three fours in a row, a period which included a total of five fours across six balls, took her to the 90s.
Harmanpreet, who was grassed on 41 by Klaas off her own bowling, straightaway slipped into rhythm and pulled Sune Luus to start her scoring.
The right-hander's aggressive intentions only grew with the innings as she punished Klaas for a four and six in successive balls.
The SA bowlers tried to curtail the free-flowing Smriti, bowling wide off her off-stump. While the strategy was worth giving a go, they erred in line so much as the India vice-captain garnered a clutch of boundaries without much effort.
She reached her hundred off 103 balls with a single off Luus, and later Harmanpreet joined her deputy with a boundary off Klaas in the final over.
India plundered 118 runs in the last 10 overs, feeding on some shoddy bowling and fielding by the visitors.
Brief Score: India: 325 for 3 in 50 overs (Smriti Mandhana 136, Harmanpreet Kaur 103 not out; Nonkululeko Mlaba 2/51).
