Australia's reserve pacemen and recalled batsmen stood up to shock India by 34 runs at the SCG, when Rohit Sharma scored 133 but couldn't overhaul the hosts' 5-288 in the ODI series opener.
However, it was a controversial dismissal of Indian talisman MS Dhoni that headlined the clash.
Dhoni was trapped lbw by debutant Jason Behrendorff for 51, having shared a 137-run stand with Rohit Sharma.
The ball was pitching outside leg stump but Ambati Rayudu had already unsuccessfully used India's only review earlier in the innings.
Fox commentator Shane Warne described the decision as an "absolute shocker".
Desperate to shore up a World Cup defence that looked in awful shape after three wins from Australia's past 21 completed ODIs, selectors made six changes.
Usman Khawaja scored 59 during his first ODI in almost two years while Peter Handscomb, playing his first ODI in 15 months, top-scored with 73 after Aaron Finch opted to bat.
Debutant Jason Behrendorff and fifth-gamer Jhye Richardson, both called up in the absence of rested guns Mitchell Starc, Josh Hazlewood and Pat Cummins, quickly reduced India to 3-4.
Behrendorff trapped Shikhar Dhawan lbw for a golden duck then Richardson, who finished with man-of-the-match figures of 4-26, removed Virat Kohli and Ambati Rayudu in the space of three balls to make the target look an imposing one.
"I'm ecstatic," Richardson said.
"It's good to put a personal performance on the board but I'm just really excited with the way Australian cricket is heading."
Sharma countered with his 22nd ODI century, sharing a 137-run stand with Dhoni as they threatened to drag the tourists to victory.
It was an epic fightback from Dhoni, whose 332 ODIs meant he boasted as much experience as Australia's entire XI, and Sharma, arguably the best one-day batsman in the world.
Behrendorff, presented his cap by Glenn McGrath, ended the partnership by trapping Dhoni lbw for 51 and the visitors eventually finished at 9-254.
"We're not very pleased with the way we played," Kohli said in the presentation.
Richardson blasted out Dinesh Karthik and Ravindra Jadeja but Sharma's six sixes and continued presence at the crease gave India's fans, well represented in the 37,556-strong crowd, some hope.
A victory equation of 75 runs from the final five overs ultimately proved insurmountable as Shama went down swinging at Marcus Stoinis.
"We kept losing wickets at the wrong time," Sharma said.
"These are the games that will teach you a lot."
Earlier, Stoinis smacked an unbeaten 47 off 43 balls as Australia batted out their full 50 overs for just the third time in nine ODIs under Justin Langer.
The absence of a collapse was a big tick, especially after Australia slipped to 2-41 when promoted opener Alex Carey joined Finch in the pavilion.
Australia failed to find the rope between the start of the 37th over and end of the 43rd over, managing only 27 runs in that stretch.
It prompted plenty of wisecracks in the commentary box about Australia's conservative approach mirroring their canary-yellow retro kit from 1986
But Australia took 80 runs off the final seven overs as Stoinis and Handscomb delivered what proved a winning score.