The Battle of Lexington was the first confrontation between Britons and Americans in the American Revolutionary War, on April 19, 1775.
During that date, the British forces were on a mission to destroy the arsenal of the patriotic militias in Massachusetts. The Americans, who had learned of this, intercepted the British forces in Lexington and sought to stop their movements without success. Consequently, they retreated to Concord, where patriotic reinforcements defeated the British, who retreated to Boston.
Thus, the Americans won in the first skirmish of the war, demonstrating to the British that their independence and revolutionary intentions were serious.