Gautam Gambhir's 92 at the top and some smart batting by captain Mahendra Singh Dhoni at the finish helped India chase down a 270-run target against Australia in Adelaide on Sunday for their second win in the triangular series.
The visitors, needing 13 runs in the last over, reached the mark with four wickets in hand and two balls to spare, aided by a huge straight six by Dhoni who remained unbeaten on 44 to see India through.
Clint McKay, the most successful bowler for Australia on Sunday with three for 53, made it easier for the Indians by bowling a no-ball in the last over.
Gambhir, who was rested against Sri Lanka in India's last match, was drafted in for Sachin Tendulkar on Sunday as part of India's rotation policy.
Left-handed Gambhir laid the foundation for India, stitching together two fifty-run stands with fellow opener Virender Sehwag (20) and later with Rohit Sharma (33) for the third wicket.
Suresh Raina (30-ball 38) and Dhoni then added 61 runs for the fifth wicket before Raina fell with India still needing 31 runs for victory.
Ravindra Jadeja also departed soon but Dhoni, known for his calm demeanour on the field, stayed till the end to ensure there were no further hiccups.
Earlier, solid half centuries from David Hussey (72) and debutant Peter Forrest (66) took Australia to 269 for eight after captain Michael Clarke opted to bat after winning the toss.
The hosts, who had won both their earlier matches in the tournament, lost openers Ricky Ponting and David Warner within the first 10 overs.
Clarke was also dismissed trying to boost the run rate after making a brisk 38, which reduced Australia to 81 for three wickets.
Forrest and Hussey then added 98 runs for the fourth wicket to lay a solid foundation and Australia looked set for a 300-plus score from there.
But India pulled things back with some tight bowling and quick wickets in the last 10 overs to restrict Australia to a smaller total.
All-rounder Daniel Christian's run out, one of the three in the innings, in the 48th over also robbed Australia of some vital momentum in the closing overs.
India play Sri Lanka at the same venue in the fifth match of the triangular series on Tuesday.