Bangladesh beat India in a Twenty20 match for the first time as Mushfiqur Rahim and Mahmudullah provided an explosive finish in Delhi.
India have lost Shikhar Dhawan for the rest of the World Cup but are backing youngster Rishabh Pant to bolster their squad in England.
India had hoped Shikhar Dhawan would return to World Cup contention but the opening batsman faces a lay-off after breaking his left hand.
India captain Virat Kohli says Shikhar Dhawan will be in plaster for "a couple weeks" but hopes his Cricket World Cup is not over.
Shikhar Dhawan could be set to miss India's next three Cricket World Cup matches due to the thumb injury he sustained against Australia.
Shikhar Dhawan's thumb injury is a cause for concern for India's medical team after he was hurt while batting at the Cricket World Cup.
India felt right at home at The Oval on Sunday, as their raucous support watched them defeat Australia in a clash of World Cup titans.
Australia's 10-match ODI winning run came to an end in a high-scoring contest, Shikhar Dhawan and Virat Kohli piling on the runs for India.
Shikhar Dhawan scored a hundred while Rohit Sharma reached a notable milestone as India made 352-5 against Australia at The Oval.