What event might a military historian use as evidence that the Americans were better fighters than the British during the American Revolution?

The Battle of Saratoga

Explanation:

The battle of Saratoga which was fought on September 19 and October 7, 1777, in which Americans came off victorious is evidence that the Americans were better fighters than the British. In that battle, British forces led by General John Burgoyne advanced towards the American forces in New York City moving Southward, with the hope that some other forces were marching Northward and Eastward to join him in the battle.

That was not to happen as the American forces who were not as experienced as the British forces trapped the General and his military men and this eventually resulted in their surrender on October 17, 1777.