Concussion substitute Yuzvendra Chahal took three wickets as India beat Australia by 11 runs in the first Twenty20 match in Canberra on Friday but the win was soured by an apparent hamstring injury to all-rounder Ravindra Jadeja.
In a contest laced with controversy, Jadeja top-edged into his helmet in the final over but was not tested for concussion on the field at Manuka Oval.
He ended up scoring a valuable nine runs off the last three deliveries to push his team to a defendable total of 161 for seven.
Jadeja, however, was ruled out during the innings break, and Australia coach Justin Langer had a heated argument with match referee David Boon before the home side began its chase at Manuka Oval.
Legspinner Chahal rubbed salt into Australia's wounds by removing captain Aaron Finch for 35 and star batsman Steve Smith for 12 in quick succession to swing the momentum back to India.
He returned to dismiss Matthew Wade for seven with the last ball of his quota, the wicketkeeper slog-sweeping to captain Virat Kohli at deep midwicket.
"Obviously it's a great feeling," Chahal beamed after being named man-of-the-match.
"It's my pleasure to take their wickets. They know the conditions very well and I bowled according to my plans."
India claimed their second successive win of the tour after beating Australia in the third one-day international on Wednesday.
But they will be without Jadeja for the rest of the T20I series, with the Board of Control for Cricket in India (BCCI) confirming the all-rounder had sustained a concussion.
"Jadeja sustained a concussion after being hit on the left side of his forehead in the final over of the first innings of the first T20I against Australia," the BCCI said in a statement.
"The diagnosis was confirmed based on a clinical assessment in the dressing room during the innings break by the BCCI Medical Team.
"Jadeja remains under observation and will be taken for further scans if required based on the assessment on Saturday morning. He will not take any further part in the ongoing T20I series."
Shardul Thakur replaces Jadeja for the two remaining games of the series.
Jadeja had called for a trainer in the 19th over as he struggled to bat with his injury but he gathered himself to hammer 24 runs off the last seven balls faced in his unbeaten 44.
Australia were also left counting the cost, with Finch suffering a muscle injury in the field and hobbling between wickets during his knock.
Australia have already lost opener David Warner to a groin injury for the T20 series and all-rounder Marcus Stoinis has been recovering from a soft tissue injury.
Opener Lokesh Rahul scored a sparkling 51 off 40 balls and left-arm seamer T Natajaran took 3-30 for the tourists, who ended up cruising to victory despite a mixed display in the field, with Finch dropped twice in successive balls.
The second of the three-match series is in Sydney on Sunday.