This affair demonstrated that Early's whole army had followed us from Fisher's Hill, in concert with Anderson and Fitzhugh Lee from Front Royal, and the two columns joined near Winchester the morning of the 18th.
That day I moved the Sixth Corps by way of Clifton to Flowing Spring, two and a half miles west of Charlestown, on the Smithfield pike; and Emory, with Dwight's and Grower's divisions (Grower's having joined that morning from Washington), to a position about the same distance south of Charlestown, on the Berryville pike.

Following these movements, Merritt fell back to Berryville, covering the Berryville pike crossing of the Opequon, and Wilson was stationed at Summit Point, whence he held a line along the Opequon as far north as the bridge at Smithfield.

Crook continued to hold on near Clifton until the next day, and was then moved into place on the left of Emory.
This line was practically maintained till the 21st, when the enemy, throwing a heavy force across the Opequon by the bridge at Smithfield, drove in my cavalry pickets to Summit Point, and followed up with a rapid advance against the position of the Sixth Corps near Flowing Spring.

A sharp and obstinate skirmish with a heavy picket-line of the Sixth Corps grew out of this manoeuvre, and resulted very much in our favor, but the quick withdrawal of the Confederates left no opportunity for a general engagement.

It seems that General Early thought I had taken position near Summit Point, and that by moving rapidly around through Smithfield he could fall upon my rear in concert with an attack in front by Anderson, but the warm reception given him disclosed his error, for he soon discovered that my line lay in front of Charlestown instead of where he supposed.
In the manoeuvre Merritt had been attacked in front of Berryville and Wilson at Summit Point, the former by cavalry and the latter by Anderson's infantry.