Ahem. The U.S navy did not stop an advance on Australia since the diggers managed to defeat the staging ground of the Japanese at PNG. This battle on the Kokoda Trail was fought all by Australia and effectively crushed any dreams Japan had about invading Australia.
By the time America arrived the Japanese had already been turned back in the north and only isolated attacks occurred on the eastern coast.
No allied nation effectively helped Australia in this time, it was done entirely by Australia.
Now to answer your question, the U.S navy managed to defeat the Japanese in the Battle of the Coral Sea. However, I might point out that America was heavily asissited by the Australian navy. This battle was not an advancement towards Australia but rather to capture various islands around the mainland in order to isolate Australia from the allies.
The Battle of the Coral Sea, from May 4 to 8, 1942, prevented a Japanese landing at Port Moresby in New Guinea. While considered a draw, or even a Japanese tactical victory, it stalled the advance of the Japanese toward the supply lines of Australia. Additionally, the Japanese had one carrier sunk and two more damaged, which may have impacted their strategy at the Battle of Midway a month later, where 4 Japanese carriers were sunk.
Battle for Australia happened in 1942.
The first battle in which the U.S. stopped the Japanese advance was the Battle of the Coral Sea, one month prior to the Battle of Midway.
The Battle of Milne Bay was fought in August-September 1942 in Papua New Guinea during World War II. It was a key battle where Australian forces successfully defended the strategic port of Milne Bay against a Japanese invasion attempt, marking the first major defeat of Japanese land forces in the Pacific War. The battle was significant as it halted the Japanese southern advance towards Australia and boosted Allied morale.
It stopped the Japanese advance, and crippled the Japanese Navy.
There were two: The battle of Coral Sea stopped the IJN's advance towards Australia, and the battle of Midway stopped their advance everywhere else; because their offensive power was destroyed at Midway (offensive power=aircraft carrier pilots and deck crewmen/the planes & carriers could be replaced, but not the airmen).
Australia was the foot hole for the allied troops to mount an attack on Japanese forces. The battle of Guadalcanal was the deciding battle in preventing the Japanese invasion of Australia.
To stop the Japanese advance on Port Moresby.
The battle marked the first time that the relentless Japanese advance had been stopped.
The Americans did not win; yet halted the Japanese advance onto Australia and Port Moresby. Both sides sustained heavy losses, ship and air.
The Japanese were on the back foot.
In the midway battle the American planes and ship defeated the Japanese ones.