Yuvraj slammed eight fours, including the winning boundary, in his 65-ball whereas Raina hit a six and couple of fours in his 28-ball blitzkrieg.
After losing Dhoni and Gambhir in quick succession, Yuvraj revived the run-chase with Raina as they added unbeaten 74-run for the sixth wicket. Brett Lee scalped Indian skipper Dhoni soon after Gambhir ran himself out in the 34th over.
Gambhir played a cautious innings as he hit just two fours in his 64-ball fifty. A miscommunication with Yuvraj Singh led to his departure after surviving similar mishap in the previous ball. India lost Virat Kohli (24) after he added a valuable 49-run with Gambhir for the third wicket against Australia.
Kohli hit only one four in his patient 33-ball innings as he resurrected India's run-chase with Gambhir after Sachin's wicket. David Hussey dismissed Kohli in the 29th over.
Shaun Tait gave Australia a crucial and much-needed breakthrough when he got rid of Sachin Tendulkar after the little master edged out Kumar Sangakkara as leading run-scorer of the tournament.
Sachin, who hit seven fours in his steady 68-ball 53, scored his 94th fifty in the one-dayers and added 50-run with Gautam Gambhir for the second wicket.
The master blaster also reached landmark 18,000 runs in one-day internationals. Sachin has already scored two hundreds in this edition and is awaiting his 100th international ton.
Chasing 261-run target, India lost Virender Sehwag (15) in the ninth over after a good start. Sehwag and Tendulkar started Indian run-chase aggressively and added 44 runs for the first wicket.
Sehwag hit two fours in his rare slow innings of 15 off 22 balls before Shane Watson gave Aussies the crucial breakthrough.
Earlier, Ricky Ponting slammed fifth World Cup hundred to help Australia set 261-run target for India in the second quarterfinal.
Ponting hit seven fours and a six in his 118-ball 104 innings as he scored his 30th ODI hundred.
R Ashwin took the prize-wicket of Ponting in the penultimate over of the match. Ashwin finished the innings with 2 wickets for 52 in 10 overs.
David Hussey remained unbeaten for the champions on 38 off 26 balls. David hit three boundaries and a huge 85 metres six during his late charge against the Indian bowlers.
Zaheer Khan dismissed Cameron White (12) and Mike Hussey (3) to halt the Australian innings in the middle overs. Zaheer scalped White after the batsman added 40-run with his skipper Ponting for the fifth wicket.
Yuvraj Singh was the pick of Indian bowlers with two wickets for 44 runs in his ten overs.
Yuvraj dismissed Michael Clarke (8) in the 31st over to check the Aussie innings.
Brad Haddin (53) scored a patient half-century and added a valuable 70-run stand with his skipper for the second wicket and slammed six fours and a six in his 62-ball innings before Yuvraj struck in the 23rd over.
Off-spinner R Ashwin provided India crucial breakthrough as he dismissed Australia's Shane Watson in the tenth over.
Openers Shane Watson and Brad Haddin started off well as they gave Australia a steady start against India. The duo added 40 runs for the first wicket.
Earlier, Australian skipper Ricky Ponting won the crucial toss and decided to bat first.
In what is Mahendra Singh Dhoni's 100th ODI as India captain, there is one change to the side with Virender Sehwag coming in for Yusuf Pathan.
Australia have brought David Hussey in place of spinner Steven Smith.
