The initial British attack was directed against the North Carolina militia, who formed a defensive line behind a rail fence. The attack was successful, but soon the British left wing found itself threatened on its flank.
The British left wing was led by Lieutenant-Colonel James Webster and consisted of the 23rd and 33rd regiments, supported by British Guards and Hessian jaegers.
According to Charles Stedman (British officer and later historian), Webster found “the left of the thirty-third regiment exposed to a heavy fire from the right wing of the enemy, which greatly out-flanked him …” 
Webster’s assailants came from a corps of cavalry, light infantry, and riflemen commanded by Lieutenant-Colonel William Washington. Early in the fighting a picked body of the riflemen were dispatched to skirmish with the British. This group (about 50 men) were led by Major John Callaway of Virginia. According to one rifleman, the men gave “the Enemys left Flank four or five destructive fires [before] the Major ordered a Retreat”. 
Stedman noted that Webster “changed his front to the left…. [and] moving to the left with the thirty-third regiment, supported by the light-infantry of the guards, and the yagers, routed and put to flight the right wing of the enemy…” 
However, the American retreat came only after a stubborn defense.
James Collins, who was with a part of the North Carolina militia, recalled that “He, with most of his company stood till they got four fires” 
Sergeant-Major William Seymour of the Delaware light infantry wrote that:
“our riflemen and musquetry behaved with great bravery, killing and wounding great numbers of the enemy. Colonel Washington’s Light Infantry on the right flank was attacked by three British regiments, in which they behaved with almost incredible bravery …” 
The first American line retreats before the British infantry. In the background are Virginian militia from the brigades of Brigadier-General Robert Lawson and Brigadier-General Edward Stevens. The 33rd Regiment of Foot (red and white flag) attacks Lynch’s riflemen while British Guards and Jaegers (bottom and right) come up to reinforce the British line.
The 33rd Foot, wheeling to the left, confronts Continental light infantry.
1. Charles Stedman. (1794). The History of the Origin, Progress, and Termination of the American War, Vol. 2.
4. William Seymour (1896). A journal of the southern expedition: 1780-1783. Papers of the Historical Society of Delaware, 15, 3-42.
The three British "regiments" possibly refer to be the 33rd Foot, the Hessian jaegers, and the Guards' light infantry company.