Chennai | Australia captain Pat Cummins opted to bat first against India after winning the toss in their World Cup opener here on Sunday.

Talented India opener Shubman Gill, who is down with dengue, could not recover in time and left-handed Ishan Kishan has been drafted in as his replacement.

"He (Shubman Gill) hasn't recovered in time. Ishan comes in to replace him, he will open the batting," Rohit said at the toss.

Teams India: Rohit Sharma (c), Ishan Kishan, Virat Kohli, Shreyas Iyer, KL Rahul (wk), Hardik Pandya, Ravindra Jadeja, Ravichandran Ashwin, Kuldeep Yadav, Jasprit Bumrah and Mohammed Siraj.

Australia: David Warner, Mitchell Marsh, Steven Smith, Marnus Labuschagne, Cameron Green, Alex Carey (wk), Glenn Maxwell, Pat Cummins (c), Mitchell Starc, Josh Hazlewood and Adam Zampa.