On the night of 8/9 August, a Japanese force of seven cruisers and a destroyer under Vice Admiral Gunichi Mikawa sneaked by Savo Island and attacked the American ships. At the time, "Astoria" had been patrolling to the east of Savo Island in column behind and . The Japanese came through the channel to the west of Savo Island and opened fire on "Chicago" – force first at about 0140 on the morning of the 9th, hitting both cruisers with torpedoes and shells. They then divided – inadvertently – into two separate groups and turned generally northeast, passing on either side of "Astoria" and her two consorts. The enemy cruisers began firing on that force at about 0150, and the heavy cruiser began return fire immediately. She ceased fire briefly because her commanding officer temporarily mistook the Japanese force for friendly ships but soon resumed shooting. "Astoria" took no hits in the first four Japanese salvoes, but the fifth ripped into her superstructure, turning her into an inferno amidships. In quick succession, enemy shells put her No. 1 turret out of action and started a serious fire in the plane hangar that burned brightly and provided the enemy with a self-illuminated target.