It was a mismatch — a small task unit of U.S. Navy ships confronted by a mighty squadron of Japanese warships.

The Americans went on the attack with every gun and torpedo that they had, repelling the enemy vessels that had threatened to cut off the supply lines for an amphibious landing led by Gen. Douglas MacArthur on the strategic island of Leyte in the Philippines.

But the heroic stand in the Battle of Leyte Gulf, the largest naval battle of World War II, came at a heavy cost: Two escort carriers, two destroyers and a destroyer escort from the task force unit, known as Taffy 3, sank.

Now, 75 years after that turning point in the Pacific theater, a private underwater expedition discovered the wreckage of one of those destroyers, which researchers believe to be the USS Johnston DD-557.

The Fletcher-class destroyer lost 186 members of its crew of 327 sailors, including its commander, Ernest E. Evans, who was the first Native American in the Navy to receive the Medal of Honor. It sank on Oct. 25, 1944.

“They were hopelessly outclassed, but they fought anyway,” said Sam Cox, a retired Navy rear admiral and director of the Naval History and Heritage Command, the preservation arm of the Navy. As the Johnston was sinking, the crew of a Japanese destroyer saluted the vessel, he said.

“They didn’t think Americans had that kind of bravery,” he said, “so that surprised them.”

Navy historians confirmed that the wreckage belonged to a Fletcher-class destroyer, but said that they needed to do more research to determine if it was the USS Johnston or the USS Hoel DD-533, which sank on the same day.

Two 5-inch gun mounts, two funnels, a propeller shaft and twisted hunks of metal are part of a debris field that was found in May by the Research Vessel Petrel in a trench 20,400 feet beneath the surface of the Philippine Sea.

It is the deepest warship wreck ever discovered, according to researchers. At that depth, there was a danger of losing the remote-operated vehicle because of the lack of buoyancy, which forced its operator to thrust the vehicle upward.

The underwater survey was conducted by Vulcan Inc., the RV Petrel’s owner and operator, which released video footage of the wreckage last week to coincide with the 75th anniversary of the USS Johnston’s sinking and to try to get confirmation that it was the destroyer that was discovered.

The private company was started by Paul Allen, a late Microsoft co-founder, and his sister, Jody Allen, to handle the family’s business and philanthropic activities, including underwater research.